White-headed woodpeckers are restricted to the western states of WA, OR, ID and CA. In WA, they are a species of concern and little is known about them - they are the least studied woodpecker in North America. White-headed woodpeckers (WHWP) are the only woodpecker with a fully black body and a white head (the male has red on the back of his head). They are non-migratory and found in conifer forest, specifically ponderosa pine.
WHWP were historically thought to be tied to old-growth forests. Jeff's research, which was the second study to ever be done on them in WA, showed that they do well in either burned or unburned trees and that there doesn't appear to be a strong link to old-growth. They do just fine in managed stands.
Jeff’s study focused on WHWP in managed forests, looking at:
Nest site characteristics
Reproductive success
The role of sexes in feeding and nest cleaning
What were parents feeding young
White-headed woodpeckers show a clear preference for ponderosa pine for nesting, and they tend to prefer fire-cleared habitats like this photo on the right, but they will make cavity nests in other trees. WHWP are weak excavators, so they tend to chip away at dead or dying trees to make a cavity. White-headed woodpecker holes are relatively small and round, very similar to hairy woodpecker holes, but on average they are just 12 feet above the ground. Because they are so low to the ground, WHWP prefer sparse canopy cover because dense shrub cover near their nest brings more danger (squirrels, weasels, martins, hawks) and less visibility.
Jeff and his research team used "tree-top peepers" (see left) to look into nest holes. They also watched birds to see what they were eating, and which sex was feeding or sitting on the eggs more. They banded birds and took habitat notes.
Jeff's research showed that males scout out potential snags, and then females decide whether they like it or not. If not, the males keep looking before they excavate. Males do most of the excavating. Females lay one egg a day (perhaps up to five eggs) and start sitting on the eggs after all the eggs are laid. The females stay close to the nest, alternating with the male sitting on the eggs and gathering food (which can be just about any insects but they especially like wood borer larvae and carpenter ants). However, males sit on the eggs most of the time, and catch larger food items. Whether they are a monogamous species is a “gray," unknown area.
Woodpeckers have hooked or barbed tongues and work them like a sewing machine, to grab grubs out of holes.
White-headed woodpeckers avoid competition for food with other woodpecker species by using different nesting periods. (Hairy woodpeckers are slightly earlier)
Figuring out the age of birds is based on primary feathers and molting. Young birds have brown primary feathers until they molt and slowly replace them with with white adult features. Males have dingy brownish white heads that slowly molt into a red stripe at the back of their white hood.
Notes by volunteer Maddie Cogswell. Thanks Maddie!
