318 ANIMAL LIFE IN THE YOSEMITE 



period of our field work there. In coloration and general behavior the 

 Willow Woodpecker resembles closely the much larger Modoc AVoodpecker 

 (see pi. 5), but it is far less noisy. It rarely has anything to do with 

 coniferous trees, foraging, rather, on soft-barked trees such as the willow, 

 Cottonwood, and, where it is available about ranches, upon the apple. 



The quietness of the Willow Woodpecker, as compared with most other 

 species in its family, is noteworthy. We heard no single call note from 

 it, and only at long intervals did we hear the indescribable short trill 

 characteristic of this bird. Individuals are much restricted in range, 

 foraging along a relatively short line of cottonwoods or willows day after 

 day. Once a bird is located, it can usually be found in the same place 

 regularly. When foraging it moves about with very little commotion, and 

 even when drilling for insects works so quietly that only a keen auditor 

 can detect its presence. No matter what the season of the year, a pair of 

 these birds is to be found usually within hearing of each other. The bird 's 

 close adherence to deciduous trees makes it more conspicuous and easier 

 to observe in late fall and winter than in the summertime when the trees 

 are fully leaved out ; but even in winter, our experience with the Willow 

 Woodpecker led us to consider it about the most elusive of all the diurnal 

 birds of the Yosemite region. 



We had always supposed that the rapid series of notes uttered by this 

 species were given only by the adult male and hence constituted a sort of 

 song. But on June 24, 1920, in Yosemite Valley a juvenile male was found, 

 with his head out of a nest hole eight feet above the ground in a dead 

 branch of a live willow, giving every few moments this very series of notes. 

 The large crown patch of red on this bird established its age and sex 

 clearly. There was every indication that the notes were being given as a 

 food call. 



A pair of Willow Woodpeckers proved to be regular tenants of Curry 's 

 apple orchard on the floor of Yosemite Valley. They, or their ancestors, 

 had evidently worked there for some years, with the result that most of 

 the 150 trees in the orchard showed marks of their attention, and many 

 of the trunks were fairly riddled with drillings somewhat like those of 

 the sapsucker. On November 8, 1915, two of us made a study of the site, 

 with the following results. 



A measured area 6 inches (15 cm.) square, 4 feet (130 cm.) above 

 ground on a trunk 121/^ inches (32 cm.) in diameter contained 17 fresh 

 pits and 30 old ones, of last year's or older digging. These pits (fig. 41) 

 Avere horizontally elliptical, each about 2.5 by 4 mm. in surface extent, 

 and therefore were distinctly different in size and shape from true sap- 

 sucker drillings. They were arranged in irregular horizontal rows with 

 spaces of 6 to 14 mm. between individual pits and 3 to 8 cm. between 



