336 ANIMAL LIFE IN THE YO SEMITE 



sion, and repeated the series about 4 times a minute. The bird Avould draw 

 its head far back, so as to move it through an arc fully 8 inches in length, 

 and the combination of long neck, heavy head, and stout sharp bill (fig. 46) 

 made for results. With every few series of strokes a large flake of dead 

 bark would fall to the ground with a clatter. Other birds, working with 

 similar industry, have been seen to throw chips fully 2 feet backward as 

 they chiseled off the dead wood. 



Another pileated woodpecker was observed working diligently on a 

 dead yellow pine in Yosemite Valley on December 24, 1914. After every 

 few taps the bird would stop and look about intently, thus bearing out the 

 impression of its wariness we had gained elsewhere. It rapidly gouged 

 away the dead pine wood, in long splinters, and often used its strong 

 bill as a pry to give the final loosening touch to a particularly large chunk 

 around which it had chiseled. The noise made, as the bird delivered 

 a blow with all the force in its long neck and powerful body, was as loud 

 as that made by a carpenter when hitting a nail. When two birds are 

 w^orking in the same vicinity the resulting noise is considerable. A pair 

 drilling near Yosemite Point on June 4, 1915, produced tones about an 

 octave apart, evidently due to differences in the wood upon which they 

 were working. 



The total amount of excavation done by these birds is surprising. 

 Many dead fir stubs seen near Aspen Valley were literally riddled with 

 surface cavities, some of which were large enough to admit a man's fist. 

 Sometimes great vertical troughs had been dug in the sides of these dead 

 and rotting trees. One such trough measured had a total volume of about 

 1040 cubic inches. Since no evidence was found of work on living timber, 

 we do not believe that the birds work on any wood that is not dead and 

 populated with insect larvae or ants. 



Examination of the stomach contents of two pileated woodpeckers taken 

 at Aspen Valley, October 16, 1915, and Sweetwater Creek, near Feliciana 

 Mountain, October 30, 1915, showed each to contain more than a hundred 

 carpenter ants (Campo7wtus lierculaneus modoc). In addition one con- 

 tained a whole manzanita fruit {Arctostaphylos sp.) and the other, 4 large 

 beetle larvae (Cerambycidae) evidently dug out of some dead tree, for 

 the stomach contained also slivers of dead wood (H. C. Bryant, 1916, 

 p. 32). 



The Northern Pileated Woodpecker sometimes departs widely from 

 its usual diet of beetle larvae and ants. For instance, on Sweetwater 

 Creek, near Feliciana Mountain, in late October, one was seen feeding 

 on the ripened fruits of the Nuttall dogwood. Because the terminal 

 branchlets which bear the fruit are small and slender, the big bird was 

 forced to hang inverted, chickadee-like, except when the clusters could 



