HAWKS 283 



The nature of the Sharp-shin's depredations may best be illustrated by 

 citing a few actual instances which came under our own observation. 

 On December 30, 1914, a hawk of this species was seen in a grove of golden 

 oaks on the north side of Yosemite Valley, flying in and out among the 

 branches, and causing evident panic in a scattering flock of Western Blue- 

 birds which had gathered there to feed on the mistletoe berries. A few 

 days later, at Snelling, a male Sharp-shin was collected which was found 

 to weigh 117 grams. The distended gullet and contents alone weighed 

 15.4 grams. Upon being opened the gullet was found to be crammed with 

 the remains of a Linnet, including both wings (which had been plucked 

 by the hawk before being eaten), the neck, one foot, and several other 

 parts. A Linnet weighs about 23 grams; since the hawk had eaten nearly 

 two-thirds of the bird, it is to be seen that it had consumed at one meal 

 a quantity of material equal to more than one-seventh of its own body 

 weight. 



The most interesting incident concerning this hawk was recorded on 

 December 26, 1914, near an occupied dwelling on the floor of Yosemite 

 Valley. The observer was first attracted by a noise which sounded like 

 that made by a weasel when caught in a trap. Upon seeking the source, 

 he discovered a female Sharp-shinned Hawk struggling with a Blue- 

 fronted Jay, a bird of nearly two-thirds its own bulk. The hawk was shot 

 and killed, but even then its grip on the throat of the jay was not relaxed. 

 Only when approached closely did the jay, apparently little injured, free 

 himself from the talons of his fallen enemy and fly away. 



The Sharp -shinned Hawk may be best distinguished from its larger 

 and otherwise almost identical relative, the Cooper Hawk, by its nearly 

 square-ended tail. (See pi. 44.) The tail of the latter species always 

 appears more or less rounded even when but slightly spread. The Gos- 

 hawk, the other bullet hawk of the region, is a giant compared with either 

 of the other two species. As compared with the Sparrow Hawk, the male 

 Sharp-shin is of about the same size, but shows more rounded wings, no 

 black streaks on cheeks, and bright reddish markings are totally lacking. 



Females of the Sharp-shin are about one-fourth longer and almost twice 

 the bulk of the males of the same species. There are decided differences 

 in coloration between the immature and the adult birds. The immatures 

 have brown backs with narrow reddish brown feather marginings and their 

 breasts are streaked, while the adults have dark bluish gray backs without 

 lighter feather margins and their breasts have a cross-barred pattern of 

 markings. There is also a difference in the color of the iris, that of the 

 young birds being yellow, that of the adults, chrome orange. 



