DRYOBATES VILLOSUS ICASTUS Oberholser
CHIHUAHUA WOODPECKER
Plate [6]
HABITS
The hairy woodpeckers of the Canadian and Transition Zones in the mountains of northwestern Mexico, southern Arizona, and southern New Mexico are referable to this race. In describing and naming it, Dr. H. C. Oberholser (1911a) characterized it as “similar to Dryobates villosus hyloscopus, but bill much smaller, and wing slightly longer. * * * This bird is decidedly smaller than Dryobates villosus leucothorectis, as well as noticeably smoky-tinged on the under surface, instead of pure white; and it is in size so very much inferior to Dryobates villosus orius, that it is readily distinguishable.”
Harry S. Swarth (1904) says of the haunts of this woodpecker in the Huachuca Mountains, Arizona: “Fairly abundant in the higher parts of the mountains, from 7,000 feet upward. They may be seen almost anywhere in that region, but for breeding purposes, seem to particularly favor the dense thickets of quaking asp.” In 1922, Frank C. Willard and I found them breeding mainly among the tall pines near the summit of these mountains, above 7,500 feet. From here to the summit, about 9,000 feet, the land is rolling, mostly in gentle slopes, and covered with a fine, open, parklike forest of tall pines of two or three species, many of them from 80 to 100 feet high. The many dead, standing trees and stumps offered suitable nesting sites for pygmy nuthatches, Mexican creepers, and Chihuahua woodpeckers. We did not see any of these woodpeckers in the spruce and fir belt, below 7,000 feet.
Nesting.—On May 7, 1922, in the pine region near the summit of the Huachuca Mountains, described above, we located two pairs of Chihuahua woodpeckers and saw some new excavations in the dead pine stubs, in which they seemed to be preparing to nest, but they evidently had not yet laid their eggs. On May 15 we returned and found two of the nests occupied (pl. 6). The first nest was about 40 feet from the ground in a dead pine stub at an elevation of about 7,900 feet; the cavity was about 15 inches deep and contained four fresh eggs. Farther up, near the summit, at about 8,500 feet, we found the second nest; this was only about 15 feet up in a large dead pine, in a hole we had previously passed by as an old one; but we saw the female enter the hole and stay there, so we chopped it out and found three heavily incubated eggs in a cavity about 12 inches deep. Frank C. Willard (1918) tells of a pair of these woodpeckers that “had nested for several seasons in the dead top of a tall pine. One winter, this broke off and lodged in the top of an adjoining pine. Even with their nest site in this apparently insecure position the woodpeckers were unwilling to leave it, and their new nest was found dug in the same old tree top in its inverted position.”
Eggs.—The eggs of the Chihuahua woodpecker do not differ materially from those of other hairy woodpeckers of similar size. The measurements of three eggs in the author’s collection are 24.6 by 17.2, 24.5 by 17.7, and 24.6 by 18.0 millimeters.
Winter.—Mr. Swarth (1904) says: “They do not seem to remain through the winter months; at any rate I saw none during February, 1903 nor did any appear until March 17, when I secured two and saw one other. Ten days later they were quite abundant. The winter of 1902-1903 was quite cold, with a great deal of snow on the ground, and it is possible that with a milder winter they might remain the year through. There does not seem to be any vertical migration on the part of this woodpecker, for I saw none below 7,000 feet, and but very few as low as that.” Bendire (1895), however, writes: “In southern Arizona it does not appear to breed in the lower valleys, but I have shot several near Tucson in winter.”