CALIFORNIA YELLOW WARBLER 187 



Common in and about the city at this period, it haunts the shade trees 

 lining the streets and the fruit trees in the gardens, but is not at all 

 partial to the outlying sections, except in the more cultivated areas and 

 the orchards. It is essentially a bird of the older settled districts, 

 wherever fruit trees and deciduous trees may abound." 



For May 6, 1924, he remarks, "These warblers drifted by all day, in 

 ones and twos or threes, straggling, but, although seemingly widely 

 separated, always within hearing distance of each other. At times 

 there will be a break when apparently none are passing, then in the 

 distance the song will be heard again, soon growing louder, as the bird 

 draws nearer, following in the wake of others that have preceded him, 

 his song in turn growling fainter in the distance after he has passed." 



Nesting. — The summer haunts and nesting habits of the California 

 yellow warbler are generally similar to those of the eastern bird. 

 Grinnell and Storer (1924) write: 



Yellow warblers nest abundantly on the floor of Yosemite "Valley. Some of 

 the nests are in growths close to water, whereas others are located in brush 

 tangles or other rank growths back some distance from the streams. A nest 

 found June 7, 1915, may be taken as fairly typical. It was 52 inches above 

 the ground in the crotch of a forking stem of a chokecherry which grew in a 

 clump of the same plant, and was shaded by a black oak. As usual it was 

 higher than wide outside, being 3^ inches in height by 3 to 3*4 inches in diam- 

 eter. The cup-like cavity was 1% inches across at the top and the same in 

 depth at the center. Shreds of bark and fiat plant fibers were the principal 

 materials used in construction, the lining being of horsehair and a few feathers. 



One nest was "4 feet above the ground in a mountain lilac {Ceanothus 

 integerrimus) ,''^ and another "was placed about 15 feet above the 

 ground in a small pine tree growing at the margin of a pond. It 

 rested on the next to the topmost whorl of branches and one side was 

 against the slender trunk of the tree." 



In the Lassen Peak region, Grinnell, Dixon, and Linsdale (1930) 

 report four nests in willows, one in a wax-berry {Symjyhoricarpos) ^ 

 cue in a snowbush, and one fastened between stems of rose and wil- 

 low at the edge of a clump of rose. 



Eggs. — Three or four eggs seem to constitute the commonest set 

 for the California yellow warbler. These are hardly distinguish- 

 able from those of the eastern bird, though they average, perhaps, 

 more heavily marked. The measurements of 40 eggs average 16.6 by 

 12.4 millimeters ; the eggs showing the four extremes measure 18.3 by 

 13.5, 17.8 by 15.0, 14.7 by 12.2, and 16.3 by 11.4 (Harris). 



Food.—Vvoi. F. E. L". Beal (1907) analyzed the contents of 98 

 stomachs of California yellow warblers, and found that the animal 

 matter amounts to 97 percent of the food, consisting wholly of insects 

 and a few spiders. 



The largest item is Hymenoptera, which amounts to over 30 percent, almost 

 half of which are ants. The remainder are small bees and wasps, some of 



