BOBIN 613 



with the parent birds. Whether any one pair of robins in the central 

 Sierra Nevada rears more than a sing-le brood in a season is not known to us. 



Not until all the eggs in a set are laid does the work of incubation begin ; 

 thenceforth it is carried on without cessation. Often the sitting bird can 

 be approached very closely before it will leave the nest. The cup-like shape 

 of the nest is such that the bird can sink its whole body down inio the 

 cavity, until only its head and tail project at steep angles above the rim. 

 Once one of our party came upon a robin as the bird sat on its nest in the 

 top of a small fir tree. The bird seemed startled by the observer's sudden 

 appearance and left the nest immediately, flying to another tree fifty feet 

 away where it began to squall loudly, making such a noise that it attracted 

 to the spot a Sierra Red-breasted Sapsucker and a Mariposa Fox Sparrow. 



Ranger Forest To\^^lsley has told us that in Yosemite Valley he has 

 seen one member of a pair of Robins (the male?) feed the other (the 

 female?) while the latter sat upon the eggs. It is our impression that most 

 of the robins which we saw abroad during the middle of the day in the 

 early part of the nesting season possessed richly colored breasts and clear 

 yellow bills, and hence were probably males. This fact "would tend to 

 substantiate Mr. Townsley's observation. 



The general nature of the robin's food has been alluded to in several 

 of the preceding paragraphs. Further remarks are in order. In the nest- 

 ing season the birds feed largely on worms and insects, but in other parts 

 of the year their subsistence is gained mainly from berry-producing trees 

 and shrubs. At Walker Lake, in mid-September, 1915, robins were feeding 

 on berries of the red elder, and at Glen Aulin, later the same month, 

 in company with Townsend Solitaires, the robins were eating the berries 

 of the western juniper. In Yosemite Valley in early November, 1915, 

 they were taking chokecherries and coffee berries, while at GentrJ^s on 

 December 30, 1914, the few robins seen were eating the dry sticky-coated 

 berries of the manzanita (Arctostaphylos mariposa). Robins are quick 

 to take advantage of easily obtained food of a sort to their liking. Many 

 persons who sojourn in the Yosemite region during the summer months 

 find the robins ready visitors to their "bird feeding tables." The picture 

 of a spotted-breasted young shown herewith (fig. 60) was obtained at one 

 of these feeding places on a porch in the Yosemite village. 



The robin's adaptability in the matter of food, and also its instinctive 

 haste to cleanse its nest of any debris, were both illustrated by an incident 

 which transpired on June 20, 1915, at Chinquapin. A robin was seen 

 to fly away from its nest nearby carrying in its bill something which looked 

 like a mouse dangling by the tail. The bird happened to drop the object 

 within the camp precincts and it proved to be a juvenile robin (with 

 feathers still in the sheaths). The old robin had obtained a large piece of 



