SAN PEDRO WOODPECKER
HABITS
The acorn-storing woodpecker of the Sierra San Pedro Martir, northwestern Baja California, has been separated and described by Grinnell and Swarth (1926) under the above name, to which they have added the long common name “San Pedro Martir acorn-storing woodpecker.” Its distinguishing characters are given as follows:
Most nearly like B. f. bairdi. Distinguished from that species primarily by shorter wing, and by slightly shorter and notably weaker, more slender bill; also by average differences in head markings as set forth below. * * *
The relatively feeble bill of this bird, as compared with that of the upper California bairdi, is the most conspicuous character of this subspecies. In bill structure it is closely similar to B. f. aculeata, of Arizona.
The character of the head markings in the female is suggestive again of aculeata, the red area being usually more nearly square, as in that form, rather than shorter than wide, as in bairdi. The white frontal band averages slightly narrower than in bairdi, an approach toward the condition in angustifrons, of the Cape San Lucas region. The yellowish white (more dilutely yellow than in bairdi) U-mark on the lower throat in both sexes averages very much narrower in our specimens of martirensis than in a large series of bairdi usually only about half the width of the former as in the latter. This we are not quite confident of as a real character, in that there is a chance that “make” of specimen (whether or not the skin of the throat was stretched) affects the width of the white band. * * *
In character of the markings on the feathers of the breast there is no departure from the condition in bairdi. The upper breast is broadly and solidly black, the black band not penetrated posteriorly with white streaks to such an extent as in aculeata and angustifrons.
The range is given as, “so far as now known, only parts of the Sierra San Pedro Martir, in northern Lower California, between latitudes 30° and 31°30″; altitude 5,800 to 7,200 feet; life-zone mainly Upper Sonoran (live-oak association), but also Transition locally or sporadically.”
The eggs are similar to those of other races of the species. The measurements of 12 eggs average 26.19 by 18.35 millimeters; the eggs showing the four extremes measure 25.1 by 19.4, 19.0 by 18.5, and 22.8 by 16.8 millimeters.