As I wanted a couple of specimens, I was compelled to disturb their jollification; those procured were both males, and presumably the entire flock belonged to this sex. By April 20 they had become very common, and some pairs at least were mated and had already selected their future domiciles, in every case a good-sized live aspen tree. The males might at that time be heard in almost all directions drumming on some dry limb, generally the dead top of one of these trees. They scarcely seemed to do anything else.
Nesting.—He says of the nesting habits in the Klamath Valley:
As far as my own observations go, healthy, smooth-barked aspens are always selected as suitable nesting sites by these birds. The trees used vary from 12 to 18 inches in diameter near the ground, and taper very gradually. The cavity is usually excavated below the first limb of the tree, say from 15 to 25 feet from the ground. The entrance hole seems to be ridiculously small for the size of the bird—perfectly circular, from 1¼ to 1½ inches in diameter only—so small, indeed, that it seems as if it took considerable effort for the bird to squeeze himself in and wriggle out of the hole.
The gourd-shaped excavation varies in depth from 6 to 10 inches, and it is from 3 inches near the top to 4 or 5 inches wide at the bottom. The finer chips are allowed to remain in the bottom, forming the nest proper, on which the eggs are deposited. Frequently they are more than half covered by these chips. The interior of the entire excavation is most carefully smoothed off, which must consume considerable time, considering the tough, stringy, and elastic nature of the wood when filled with sap, making it even more difficult to work when partly decayed, which seems to be the case with nearly all the aspens of any size. Probably eight or ten days are consumed in excavating a satisfactory nesting site. All the larger and coarser chips are dropped out of the hole and scattered about the base of the tree.
Johnson A. Neff (1928) says: “The nests of these birds are placed in whatever trees are abundant in their vicinity. In Klamath County, in the foothills and in the lower valleys, alders, cottonwoods and aspens were utilized; in the higher altitudes, firs were the common site, with the alder and willow along the small streams. In the Willamette Valley the firs, cottonwoods, willows, alders, and others, are used indiscriminately.”
Near Blaine, Wash., Mr. Dawson (Dawson and Bowles, 1909) found an almost inaccessible nest of this sapsucker 50 feet from the ground in a big fir stub, “sixteen feet around at the base, above the root bulge, and perfectly desolate of limbs.” He managed to reach the nest with the help of a rope and cleats nailed on the barkless trunk. He says:
“By the time I had a hole large enough to thrust in the hand, the eggs were quite buried in chips and rotten wood. But when they were uncovered, they were seen to lie, seven of them, in two regular lines, four in the front rank with sides touching evenly, and three in the rear with points dove-tailed between.”
Harry S. Swarth (1924) also found some lofty nests in the Skeena River region of northern British Columbia; he writes: “During May and June a number of nests were found, mostly through seeing the old birds carrying food to the young. One was drilled in a live poplar, the tree a straight column with no branching limb save at the very top, the nest some seventy feet from the ground. Another was in a dead birch, sixty feet up. Many others were noted, all in birch or poplar, mostly dead trees, and no nest was less than fifty feet above the ground. One male bird collected had the abdomen bare of feathers. It obviously had been incubating eggs.”
Eggs.—The red-breasted sapsucker lays four to seven eggs, usually five or six. Bendire (1895) describes them, as follows: “The eggs, when fresh and before blowing, like those of all Woodpeckers, show the yolk through the translucent shell, giving them a beautiful pinkish appearance, as well as a series of straight lines or streaks, of a more pronounced white than the rest of the shell, running toward and converging at the smaller axis of the egg. After blowing, the pink tint will be found to have disappeared and the egg changed to a pure, delicate white, the shell showing a moderate amount of luster. There is considerable variation in their shape, running as they do through all the different ovates to an elongated ovate.”
The measurements of 54 eggs average 23.61 by 17.51 millimeters; the eggs showing the four extremes measure 25.40 by 17.78, 24.13 by 18.54, 21.84 by 17.27, and 23.11 by 16.26 millimeters.