BLACK-HEADED GBOSBEAK 



489 



Four is the usual number of eggs laid although we saw sets of both 3 

 and 5 in which incubation had commenced. Several nests seen held 4 

 young but no iinhatched eggs, indicating that all the eggs in these par- 

 ticular sets were fertile and had hatched successfully. 



During their residence here the black-headed grosbeaks levy upon a 

 wide variety of materials for food. At Snelling, on May 26, 1915, the 

 birds were feasting on the wild blackberries which were then ripening 

 in abundance. At Pleasant Valley at the same season, males were noted 

 on the ground in search of insects. At Lagrange birds of both sexes were 



Fig. 55. (a) Young Mariposa Fox Sparrow; Chinquapin, July 13, 1915. (b) Young 

 Pacific Black-headed Grosbeak; Pleasant Valley, May 25, 1915. 



seen flying out from the trees to capture passing 'bugs.' In Yosemite 

 Valley Mr. Joseph Mailliard records (1918, p. 14) that he saw family 

 parties of these birds foraging in barnyard chaff at the " Kenney ville " 

 stables; grains from the dried stalks of oats, wheat or barley were being 

 picked out. At Mono Lake Post Office on May 21, 1916, two males were 

 seen feeding upon the hearts of cherry blossoms. These birds were work- 

 ing rather rapidly and a blossom would drop every fifteen or twenty 

 seconds. 



The black-headed grosbeaks in Yosemite have become accustomed to 

 the presence of people and also have learned to patronize habitually the 

 bird-feeding tables, which many persons establish during the period of 



