Impossible as it would seem at first sight, I have found that the snow-white head often serves the bird as a disguise. It is the disguise of color pattern, for the black body seen against a tree trunk becomes one of the black streaks or shadows of the bark, and the white head is cut off as a detached white spot without bird-like suggestions. On the other hand, when the bird is exploring the light-barked young Shasta firs or gray, barkless tracts of old trees, the white of the head tones in with the gray and is lost, the headless back again becoming only a shadow or scar. But the most surprising thing of all is to see the sun streaming full on the white head and find that the bird form is lost. The white in this case is so glaring that it fills the eye and carries it over to the light streaks on the bark, making the black sink away as insignificant. The activities of this and other woodpeckers play an important role in the welfare of the forests and the lives of the little furred and feathered denizens of the woods. It is a well-known fact that woodpeckers are most useful in guarding the living trees and destroying the insect pests that injure them; but Grinnell and Storer (1924) have called our attention to the fact that woodpeckers in general, and the white-headed woodpecker in particular, contribute, by their excessive drilling of nest holes, “rather directly toward bringing down the standing dead timber.” They continue: Drilling by woodpeckers results in an increase in the number of entrances through which insects may get at the heart wood of a tree and thus hasten its ultimate disintegration. Water, also, is thus afforded an easier entrance and this hastens decay. Eventually each and every tree must yield its place in the forest to seedlings. The woodpeckers hasten this process of replacement, once the tree is dead. Many of the wood-inhabiting animals depend upon this woodpecker to furnish them convenient nest holes or retreats. We have found mountain chickadees and slender-billed nuthatches incubating their own eggs in holes drilled in earlier years by the white-headed woodpecker; a Sierra flying squirrel was found occupying an old white-head’s hole. Probably, tree-dwelling chipmunks and perhaps California pigmy owls also occupy holes of this woodpecker. DISTRIBUTION _Range._--Pacific coast of the United States; occurring rarely in southern British Columbia; nonmigratory.