HAWKS 



285 



ing, willow-bordered stream in a meadow. In silhouette the nest could 

 easily be mistaken for one of the many clumps of mistletoe which grew 

 in several of the oaks in the vicinity. It was composed of sticks, and placed 

 against the main trunk on smaller horizontal branches giving the needed 

 support. 



The three young hawks were perched about 30 feet above the ground in 

 trees near the nest. Since their wing and tail feathers were not fully out 

 of the sheaths, the birds could 

 not have been long from the 

 nest. Yet when frightened they 

 were able to fly away far 

 enough to hide more or less suc- 

 cessfully in the forest. 



One of the young hawks was 

 shot and upon examination was 

 found to have in its gullet the 

 scalp, eyes, brain, one kidnej^ 

 and some other parts of an 

 Allen Chipmunk (Etttamias 

 senex), a Canadian Zone species, 

 not known to occur anywhere on 

 the floor of the Yosemite Valley, 

 which is itself in the Transition 

 Zone. On this same day one of 

 the parent birds of this family 

 was seen circling high overhead 

 in the direction of Yosemite 

 Falls and may then have been 

 going to forage above the rim of 

 the Valley. It is a well-known 

 habit with this hawk, never to 

 forage in the near vicinity of its nest, but to seek its prey far afield, 

 presumably so as to avoid any risk of disclosing the location of its own 

 brood. We may thus explain the apparent foraging of a pair of hawks 

 in another life zone, while their nest was located in the zone to which 

 the species characteristically belongs. The bird observed July 2, 1915, at 

 Dark Hole, in the basin of the upper Yosemite Creek, a point well within 

 the Canadian Zone, may well have been one of the pair nesting nearly 

 4000 feet lower, altitudinally, on the floor of Yosemite Valley. 



On the ground below the nest in question we found a large amount 

 of evidence relating to the food habits of the Cooper Hawk. Some of this 

 material, comprising picked bones of victims, scattered feathers, and pellets 



Fig-. K8. Pellets and other debris picked up 

 from beneath nest of Cooper Hawk in Yosemite 

 Valley, July 25, 1915. About % natural size. 

 See text for analysis. 



