BIRDS OF PENNSYLVANIA. 83 



clump of willow, to which I had approached unobserved by the bird. 

 It had been devouring a Ptarmigan, which it had secured but a little 

 while before. The flesh of the bird was yet warm, though nearly all 

 devoured. The Goshawk was only wing-tipped with shot and proved 

 to be quite vicious, seizing my boot with its talons arid striving to 

 grasp my hand with its beak. The bird was so quick that I had to 

 call the assistance of a native to detach the claws from my clothing. 

 Upon skinning the bird I found its crop to be full of the flesh of the 

 bird it was eating when I flushed it. I am under the impression that 

 the Goshawk is not able to fly with the weight of a Ptarmigan in its 

 claws. It is a resident of the interior and comes to the coast quite 

 early in spring, as is attested by the fact that I killed one specimen 

 April 28, and a fine example was brought to me from the mouth of 

 the Uphun (part of the northern Yukon Delta), where it was killed 

 April 25. It was a female, and contained an egg quite ready for ex- 

 trusion, and had already received a pale bluish- green color on the 

 shell. The bird was shot while on the nest, placed in a small poplar 

 tree. The nest was composed of sticks and a few blades of grass. 

 The size was quite bulky, measuring nearly two feet in extreme diam- 

 eter, and having but a slight depression. The bird was extremely 

 vicious, choosing to remain on the nest rather than desert it. The 

 male attacked the native, and tore his cotton shirt into shreds and 

 snatched the cap from the head of the astonished man, who was so 

 surprised, at the impetuosity of the attack, that he struck wildly at 

 the bird with his arms, and before he could reload his gun the bird 

 took flight. This Goshawk breeds wherever found in summer, placing 

 its nest in a tree or shrub, or even on the ledge of a cliff, inaccessible 

 to foxes and enemies." 



GENUS BUTEO. CUVIER. 

 337. Buteo borealis (GMEL.). 



Red-tailed Hawk. 



DESCRIPTION. {Plate 15.) 



The adult is easily recognized by the red tail. The tail in young birds is usually 

 ashy-brown, with about ten darker bands. Tail in both old and young is generally 

 tipped with white. Breast of adult mostly spotted or marked with reddish-brown ; 

 in the young, breast is pure white enclosed by numerous dark markings. Length 

 of male, 19 to 22 inches ; extent of wings, 41 to 47 inches. Female length, 22 to 24 

 inches ; extent, 51 to 55 inches. From a careful examination of over one hundred of 

 these Hawks, I have found that they, like other of the raptores, not only vary greatly 

 in the markings of their plumage, but also show marked differences in the color of 

 the irides. The iris of the adult, though usually brown, is sometimes both brown 

 and yellowish. In immature birds, the iris is commonly straw color, but sometimes 

 it is nearly white, and occasionally, though rarely, is brown ; in other specimens, I 

 have seen one-half of the iris brown while the remainder would be white or yel- 

 lowish. In immature birds, light colored irides with specks of brown are frequent. 



Hob. Eastern North America, west to the Great Plains. 



