“In the Yosemite Valley, these birds nest in the trunks and large limbs of the Kellogg oaks, and their abandoned holes may be used by pygmy owls another year. As a rule, the California woodpeckers and the pygmy owls show little antagonism toward each other. In spite of this usual custom of nesting in the oaks, most of the birds I saw in the Yosemite were actually in the cottonwoods along the river. After some searching, I found at least one nest there in a short, dead stub of a cottonwood, on July 24, 1933. I saw one bird fly down and feed another that was inside, and then fly away. The hole was about 12 feet above the ground and on the north side of the stub, facing the river and away from the meadow behind it. All the trees in the vicinity were cottonwoods, but there was one oak 150 feet east of the nesting site. There were six other holes in the stub, all on the north side and from 6 to 18 feet above the ground.” Grinnell and Storer (1924) write: The more intensive occupancy of the Yosemite Valley during recent years and the operations of the government employees in promptly removing dead but standing trees to be cut up for wood has operated to the detriment of the woodpeckers which seek such trees for nesting holes. So it was no surprise, in May, 1919, to find a number of telephone or electric power poles near Redwood Lane which had been prospected for nesting sites by woodpeckers--the California, to judge from the size of hole and general location. Dearth of suitable natural sites had forced the birds to at least investigate these newly established dead-tree substitutes. With no substitutes at all available, the only result to be logically looked for, as a result of man’s interference with the natural order of affairs, would be the disappearance of woodpeckers. The question arises here as to the justification of the administratiton in so altering natural conditions in National Parks as to threaten the persistence there of any of its native denizens. _Eggs._--The California woodpecker lays ordinarily four or five eggs; six eggs are not very rare; and as many as ten have been found in a nest, probably the product of two females. The eggs vary from short-ovate to elliptical-ovate. They are pure white, with very little or no gloss. The measurements of 52 eggs average 25.98 by 19.78 millimeters; the eggs showing the four extremes measure =29.9= by 19.0, 27.9 by =22.6=, =22.0= by 18.6, and 24.38 by =18.29= millimeters. _Young._--The period of incubation is said to be about 14 days, in which both parents assist. Both also help to feed the young. Harriet Williams Myers (1915) made some interesting observations on a late brood of young California woodpeckers, which she found in a hole in a telephone pole, on September 11, between Los Angeles and Pasadena. She says: