The number of eggs laid to a set varies from three to six; those of four are by far the most common; sets of five are only occasionally met with, while sets of six are very unusual. * * * The eggs lie on the fine chips left in the bottom of the cavity, and are occasionally well packed into these, so that only about one-half of the egg is visible. They resemble the eggs of Dryobates villosus in color, but those of an elliptical ovate shape are more common than the oval and elliptical ovals, averaging, therefore, more in length, while there is proportionally less difference in their short diameter.
The measurements of 23 eggs average 24.49 by 18.38 millimeters; the eggs showing the four extremes measure 25.7 by 18.2, 24.2 by 19.7, 22.8 by 18.1, and 24.9 by 16.5 millimeters.
Young.—Mrs. Irene G. Wheelock (1904) says: “Both sexes share the labors of excavating, brooding the eggs, and feeding the young. Incubation lasts about fifteen days, and the young remain nearly four weeks in the nest, being fed most of that time by regurgitation. After leaving they are fed by the parents for at least two weeks, and usually return to the nest at night to sleep.”
Food.—W. Leon Dawson (1923) writes: “Nearly half of the Cabanis Woodpecker’s food consists of the larvae of wood-boring beetles (the Cerambycidae and Buprestidae); and of the remainder the caterpillars of various injurious moths form a large per cent. Wild raspberries and blackberries are eaten in summer, and certain hardy fruits, such as cornel berries, acorns, and the pits of the islay, or evergreen cherry (Prunus ilicifolia), eke out the winter sustenance.”
Referring to its manner of feeding, Milton P. Skinner says in his notes: “On August 10, 1933, I saw a Cabanis working on both the trunk and the limbs of a small Douglas fir. It worked all around a horizontal limb and really seemed to be under the limb more than above. It also worked on upright branches as well. I have also seen a Cabanis feeding on the bark of a lodgepole pine. One day I found one on a dead black oak, scaling off dead bark to get at the insects beneath. So far as I can tell, these birds, in the Sequoia National Park, seem to prefer to pick food from the surface and furrows in the bark, and do not bore into the bark and wood as much as other woodpeckers. During my work among the Big Trees, I noticed that these birds seem to avoid the sequoia’s bark; but at one place I found a living tree with many holes bored in the old wood of its charred base, where it was unprotected by bark.”
Behavior.—Mr. Skinner’s notes say that “this woodpecker has quite a few mannerisms of its own. One, seen flying across a meadow, went first to the limbs of Douglas firs, then to a small dead limb of a sequoia, then to the limb of a fir, and then to the trunk of the same fir. It perched lengthwise of limb and trunk each time. And this procedure was followed again and again on different days. Usually the Cabanis perches crosswise on a horizontal limb, especially when resting or preening, but lengthwise on erect, or nearly erect, trunks and limbs when feeding.
“Although this woodpecker almost always flies to the exact spot it selects, its flight through the forest is undulatory. The undulations are due to the fact that it progresses by a series of wing beats. At the end of each series, it seems to actually close its wings and shoot forward with the impetus gained.”
DRYOBATES VILLOSUS MONTICOLA Anthony
ROCKY MOUNTAIN HAIRY WOODPECKER
HABITS