488 ANIMAL LIFE IN THE YOSEMITE 



In late May and during June it is a relatively easy matter to locate 

 occupied nests of the black-headed grosbeak, for the male bird does much 

 of its singing within a hundred feet of the nest and often even while 

 actually on the nest. Several nests in Yosemite Valley were found by 

 following up singing males. On one occasion, while one of us was walking 

 along the road near the Royal Arches, a female flew across the road to a 

 black oak in which the male had been perching. After giving a few calls 

 she flcAv away. The male then flew directly over the observer, alighting 

 in the same general vicinity whence the female had first come. After a 

 minute he hopped farther onto what was then seen to be the nest. The 

 bird sang a number of times, spicked between songs, and then worked him- 

 self down close over the eggs so that only his head and tail showed above 

 the low rim of the nest. Another male bird, on a nest in a black oak at 

 the roadside, was watched from a distance of but 15 feet. He sang snatches 

 of song off and on for many minutes; each utterance was marked by an 

 up-and-down twitching of the tail, which projected over the edge of the 

 nest and could be easily seen beating time, as it were, to the 'rhythm of 

 the singing. 



Still another nest of the black-headed grosbeak was found in a coffee- 

 berry bush on the north side of Yosemite Valley on the morning of June 

 19, 1915 (Mrs. Joseph Grinnell, MS): Some workmen had removed all 

 adjacent shrubbery a few days previously, evidently leaving this bush 

 only because of the nest. Originally the site had possessed a measure of 

 seclusion, but now it was exposed to the view of all passers-by. Attention 

 was quickly drawn to the nest by the male voicing his loud song as he 

 brooded the four small young. The latter were clad in the white natal 

 down which was about one-fourth of an inch in length and quite thick, 

 though the yellowish pink skin showed through in places. At sundown 

 the same day, when we passed, the female was seen to be brooding. Next 

 morning at 8 :30 the male was seen to feed each youngster in turn and then 

 brood them. At 5 :30 this second afternoon the female was again on the 

 nest. On June 26 the eyes of the young were open. The nest was not 

 watched further, but the young must have left soon afterward. 



No nest of the black-headed grosbeak was watched continuously ; but 

 brief observations on a number of nests including others than those 

 specifically mentioned above make possible the following summary. Court- 

 ing and selection of mates is carried on after the birds arrive within their 

 summer haunts. The female alone gathers nest material. After the eggs 

 are laid both members of the pair engage in the function of incubation. 

 When the eggs hatch the male does a good share of the food-gathering and 

 brooding. The young (fig. 556) remain in the nest at least 8 days, and 

 likely somewhat longer. The male sings frequently while on the nest, both 

 before and after the eggs hatch. 



