. Animal life in the Yosemite; an account of the mammals, birds, reptiles, and amphibians in a cross-section of the Sierra Nevada. Zoology. WOODPECKEKS 3H3 another close by, 44 inches. Individual punctures in a row were to inches (10 to 15 mm.) apart. Three typical fresh punctures all meas- ured inches (4 mm.) higfh, with respective widths of , , and inches (5, 9, and 10 mm.). The nearly constant vertical dimension, just as in the case of the drillings of the Red-breasted Sapsucker, was probably due to the size of the bird's bill, while the varying horizontal dimension
. Animal life in the Yosemite; an account of the mammals, birds, reptiles, and amphibians in a cross-section of the Sierra Nevada. Zoology. WOODPECKEKS 3H3 another close by, 44 inches. Individual punctures in a row were to inches (10 to 15 mm.) apart. Three typical fresh punctures all meas- ured inches (4 mm.) higfh, with respective widths of , , and inches (5, 9, and 10 mm.). The nearly constant vertical dimension, just as in the case of the drillings of the Red-breasted Sapsucker, was probably due to the size of the bird's bill, while the varying horizontal dimension resulted from varying amounts of work done in the individual pits. Many of the holes were bleeding and probably would have been visited again and again by the sapsucker. Earlier drillings of the current season had stalactite-like streamers of hardened pitch below them, some being 2 feet in length. In addition to the exudation of sap, these series of puncturings cause responsive growth action on the part of the tree. Rings or swellings in the wood and bark develop at the sites of the punctures. A tree drilled to the extent of the one described above would in a few years show a series of swollen rings, one at each line of punctures (fig. 45). And the site of each individual punc- ture develops into a small knot- like growth. A dead lodgepole pine at Aspen Valley showed clearly that it had been drilled extensively in earlier years; for the dead and partly barkless bole was little more than a suc- cession of swollen rings. Many trees exhibiting intermediate stages in this scar-like affliction were observed. During the winter months when sap is practically at a standstill in the coniferous trees at high altitudes, the William- son Sapsucker must needs seek other fare. A few of our own observations added to those of other naturalists suggest that during the winter season the birds may forage in large part on dormant insects or on insect larvae hidden in crevices in the bark. If such
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Keywords: ., bookauthorgr, bookcentury1900, bookdecade1920, booksubjectzoology
