486 ANIMAL LIFE IN THE YO SEMITE 



stripe over each eye and another over the cro-^m. The big bill, in either 

 sex, can easily be made out at ordinary field distance, and in making 

 identifications, its presence helps to rule out other birds of roughly similar 

 appearance. 



Some spring breeding males exhibit a plumage intermediate between 

 those just described for the adult male and female. In these "peculiar" 

 birds some or all of the flight feathers in the wings and tail are old, faded, 

 and worn, much more so than in males which are in the black plumage. 

 This condition of the flight feathers shows that the birds which wear them 

 are from broods of the previous season and therefore are just under a 

 year in age. The small percentage of these differentlj' plumaged birds 

 suggests that they represent cases of incomplete molt. Reports of 'singing 

 females' are probably explained by the fact that these so-called singing 

 females are males in this more or less immature condition of plumage. 



The black-headed grosbeak possesses a rich voluble song that forces 

 itself upon the attention of everyone in the neighborhood. In fact at the 

 height of the song season this is the noisiest of all the birds. The song 

 resembles in some respects that of a robin, and no\'ices sometimes confuse 

 the two. The grosbeak's song is much fuller and more varied, ' contains 

 many little trills, and is given in more rapid time. Now and then it bursts 

 forth fortissimo and after several rounds of burbling, winds up with a 

 number of 'squeals,' the last one attenuated and dying out slowly. 



Early in the season the males are to be seen, now and then, in ecstatic 

 song flights. These are most likely to occur just as the sun touches the 

 tops of the trees in the early morning. Launching forth on a horizontal 

 course, circling out from the summit of a tree, with wings and tail spread 

 to fullest extent, every feather seemingly held tense, the bird utters an 

 almost continuous ' ' bold breathless, bubbling song, ' ' richer and fuller even 

 than the usual utterance and almost torrential in its delivery. 



Of lesser notes there is a sharp explosive call or alarm note, spink or 

 spick, sometimes repeated at short intervals and given by both males and 

 females. The males are in song upon their arrival in spring and continue 

 to sing until some time in July (July 15, 1920, at Dudley). Thenceforth, 

 until the departure of the species in September, onlj^ the sharp call is 

 given and this but seldom. The young have a distinct call, a soft musical 

 whistle. This note is to be heard coming from berry patches and fruit 

 trees all through the summer. The adults at nesting time evince extreme 

 concern for their broods, and if their precincts are raided give voice to 

 squalls, loud and ear-piercing. The effect, as demonstrated in our own 

 experience, is to absorb the invader's attention so that he fails to look 

 farther for the eggs or young. 



