Sphyrapicus varius nuchalis usually insists upon a new excavation each year. The height of the nesting sites from the ground varies from 5 to 30 feet; the full set of eggs is four or five in number; sometimes a smaller number of eggs mark a full set, presumably the nest of one of last year’s birds. Fresh eggs may be looked for in Colorado from June 1 to 15, and should the first set be taken, a second one may generally be found from ten to fifteen days later; and, as a rule, the second nesting site will not be greatly distant from the first one. Several nests of this species may be found within a short distance of each other in the same aspen grove.
Eggs.—Major Bendire (1895) says of the eggs: “The number of eggs to a set varies from three to six, usually four or five; these are mostly ovate in shape, a few are more elliptical ovate; they are pure white in color; the shell is fine grained and moderately glossy.” The measurements of 40 eggs average 22.89 by 17.28 millimeters; the eggs showing the four extremes measure 24.38 by 16.76, 23.60 by 18.50, 20.83 by 16.76, and 21.34 by 16.26 millimeters.
Young.—Major Bendire (1895) says: “I believe that both sexes assist in the labor of excavating the nesting site, the female appearing to do the greater part of the work, however, which is frequently very laborious, and that the male also shares the duties of incubation, which lasts about fourteen days.”
Food.—Again, he writes: “Its general habits are similar to those of the preceding species [yellow-bellied sapsucker], and in the fruit-growing sections within its range, in southern Utah, for instance, it is said to do considerable damage to the orchards in the early spring and again in the fall, tapping the peach and apple trees for sap in the same manner as Sphyrapicus varius does in the East. Its principal food consists of small beetles, spiders, grasshoppers, ants, and such larvæ as are to be found under the loose bark of trees, as well as wild berries of different kinds.”
W. L. McAtee (1911) gives a long list of trees that are attacked by this species of sapsucker, among which this western race is charged with doing considerable damage to many western trees, such as various pines, spruces, hemlocks, firs, redwood, cedars, cypresses, junipers, cottonwoods, aspens, willows, bayberry, walnuts, hophornbeam, white alder, oaks, laurels, sycamores, mahoganies, pears, apples, cherries, mesquite, ironwood, maples, Ceanothus, Fremontia, western dogwood, madrona, buckthorn, ashes, and probably others.
Dr. Joseph Grinnell (1914) says, referring to the Colorado Valley, where this sapsucker was evidently wintering among the willow thickets: “Willows were the trees attacked by this woodpecker; but in one case a single large mesquite, and the only one of many in the vicinity, had been selected for bleeding, and its main trunk and larger branches were plentifully bored. I visited this tree many times during the space of three days, March 2 to 4, opposite The Needles, and invariably found a sapsucker working about the borings. I shot two of the birds at this mesquite, and there was still one there the last time I visited the tree, although I had never seen but one at a time there.”
W. L. Dawson (1923) remarks: “In lieu of maple sap the western bird makes heavy requisition on the fresh-flowing pitch of pine and fir trees. As for cambium, that of the aspen (Populus tremuloides) has marked preference, and the summer range of the bird, so far as it goes, is practically controlled by the occurrence of the tree. Inasmuch as this tree is short-lived and of slight economic importance, the depredations of the bark-eaters are not seriously felt.”
Mr. Skinner says, in his Yellowstone Park notes: “I have seen the red-naped sapsucker pick and hammer on dead aspens and on the trunks of lodgepole pine for insects. On June 28, 1917, I saw one make frequent flycatcher-like sallies from an aspen out into the open.”
Behavior.—John H. Flanagan (1911) witnessed a rather remarkable performance by a red-naped sapsucker, such as I had not seen recorded elsewhere. He had chopped out a nest containing two fresh eggs and was intending to leave them for a possible addition to the set, as he had done successfully before, when one of the birds, “both of which remained in sight, flew to the tree, perched a moment upon the edge of the cut hole, then went in, and shortly reappeared with one of the eggs in its beak. It flew to a nearby stub, not more than forty feet from where” he “was sitting, calmly devoured the egg and dropped the empty shell.”
Winter.—Apparently the fall migration of this woodpecker consists largely of a withdrawal from the high altitudes, in which it breeds, to winter resorts in the lowlands. Major Bendire (1895) says: “During the winter months, I have occasionally observed a red-naped sapsucker in the Harney Valley, in Oregon, busily engaged in hunting for food among the willow thickets found growing along the banks of the small streams in that sagebrush-covered region, often long distances away from timber of any size.”