276 ANIMAL LIFE IN THE YOSEMITE 



Vernal Falls. While some of the birds were thus enjoying repose, others 

 in the neighborhood were to be found seeking acorns in the densely foliaged 

 golden oaks bordering the trails. At times, a bird which was perched high 

 on the Valley wall, would take flight and precipitate itself into the caiion 

 below, going at lightning speed, with wings set almost at its sides, and 

 body veering slightly from side to side. The sense of the vast depth below 

 was intensified by this downward rush, for although it was made too 

 swiftly to permit the eye to focus upon the bird as it flashed by, yet the 

 pigeon remained in view for some seconds before it reached the vanishing 

 point in its downward course. 



One would surmise from the relatively large size of these pigeons that 

 they would be conspicuous when perched in open trees such as black oaks ; 

 but such is not the case. It often happens that the first intimation of 

 the presence of a flock of pigeons comes when one or more leave pre- 

 cipitately on loudly clapping wings and make off in direct course to some 

 other perch. The birds get under way with surprising rapidity, due to 

 the forceful jump by which they launch into the air and also to the initial 

 strokes of their wide-sweeping wings. A small flock perched in the top 

 of a dead pine was seen to leave with such force that several of the dry 

 weathered branches were broken by the vigorous jumps of the birds. The 

 crashing of the falling branches and the clapping of the pigeons' wings 

 made a vivid impression upon the observer. When a flock of pigeons is 

 engaged in foraging, a person can often hear them at a considerable 

 distance, for the birds flap noisily as they change their positions or seek 

 to balance their heavy bodies on the slender twigs. 



The manner of foraging and of eluding approach in the open is well 

 illustrated by the behavior of a large flock watched on the floor of Yosemite 

 Valley near Indian Creek on the afternoon of April 28, 1916. Our note- 

 book record reads : 



At the edge of a newly planted grain field where tree shelter was near, fully a 

 hundred of the big blue birds were feeding on the ground. They moved forward as 

 a flock, several feet a minute, those in the rear continually flying up and beyond those 

 at the front. At my distant approach they all flew vip into the adjacent yellow pines 

 and cottonwoods; the flapping of their wings as they arose produced a surprising amount 

 of noise, and as they alighted the ends of their fan-shaped, spread tails gave the effect 

 of a scattered series of white crescents against the dark green trees. The birds con- 

 tinued wary and as I came under their perches they flushed in small parties or singly 

 and flew to another clump of trees some distance away. From there, as I followed, they 

 made off in one large band and three smaller ones, circling widely out over the field. 

 As they left, the only color impression I got was of dark blue, but later, when outlined 

 in flight against the sky, the pinkish blush of their breasts was clearly seen. 



A few days later, opportunity was afforded to observe at closer range 

 a small flock in the dooryard of a home among the black oaks on the north 

 side of the Valley (pi. 43a). 



