DRYOBATES ALBOLARVATUS GRAVIROSTRIS (Grinnell)
SOUTHERN WHITE-HEADED WOODPECKER
HABITS
Dr. Joseph Grinnell (1902), in describing and naming the white-headed woodpecker of the mountain ranges of southern California, gave as its characters: “Similar to Xenopicus albolarvatus but bill much heavier, and size in general slightly greater.” He named it as a distinct species, on the theory that “the material at hand does not justify subspecific treatment of these two forms. Geographical continuity of ranges possibly exists; but it seems quite as likely that there is a broad hiatus in the vicinity of Tehachapi Pass, whence I can find no record of the white-headed woodpecker.”
The range of this form includes the San Gabriel, San Bernardino, San Jacinto, Santa Rosa, and Cuyamaca Mountains in southern California. Dr. Grinnell (1908) found this woodpecker rather scarce in the San Bernardino Mountains, and says: “They were seen only in the Transition zone, none being observed above the fir belt, and but very few down into pure yellow pine tracts. In the vicinity of Fish creek, 6,500 feet, a few pairs were breeding in June. On July 5, 1905, I found a nesting hole seven feet up in a dead pine stub, which contained four half-fledged young. We did not see the species anywhere higher than 8,000 feet, except on the south slope of Sugarloaf, where on July 11, 1906, one was seen among the silver firs at about 9,000 feet altitude. About Bluff lake they were more common than anywhere else, and a few were seen on the northern slopes of Sugarloaf at about 8,000 feet, in August.”
W. L. Dawson (1923) writes: “In the San Jacinto Mountains, where these white-heads outnumber all other woodpeckers combined, our attention was drawn, on the 6th day of June, by a male who tittered anxiously as we stumbled along the rough trail. We camped on the prospect immediately, but it took a full hour to trace the ‘damage’ to a hole fifty feet up in a yellow pine stub, which was three feet through at the base. * * *
“We found a clean-cut round hole, one and a half inches in diameter, which gave admission to a cavity ten inches deep, and which had for its outer wall only the thick bark of the tree.”
Frank Stephens wrote to Major Bendire (1895): “Xenopicus albolarvatus is a resident of the pine regions of southern California, but is not common excepting possibly in a few localities. I have never observed it below the pines. I have taken incubating birds in June in the Cuyamaca Mountains at altitudes of about 7,000 feet. The nesting sites here were in very large dead pine trees and inaccessible.”
This woodpecker seems to show a tendency to nest, at least occasionally, at greater heights above ground than its northern relative, but otherwise its habits seem to be very similar.
The eggs are similar to those of the northern race. The measurements of 20 eggs average 24.67 by 18.60 millimeters; the eggs showing the four extremes measure 26.70 by 19.50, 25.60 by 19.70, and 22.62 by 16.67 millimeters.