Birds 73 



the two outer primaries emarginate. If the head has on each 

 side a pair of vertical black stripes, the bird is the American 

 Sparrow-hawk (F. or Cerchneis sparverius). This is a very common 

 bird, feeding principally on insects; specimens from the western 

 part of the State are paler, and are referred to a subspecies phalaena. 

 There remains a species without the black stripes on sides of face, 

 the adult male above bluish-slate, most of the feathers with a 

 black central line. This is the Pigeon Hawk (Falco or Tinnun- 

 culus columbarius), usually observed on migration. In a few 

 places in the mountains Richardson's Pigeon Hawk (F. c. richard- 

 soni) has been observed; it has the outer webs of the primaries 

 spotted with white. 



The Buteonidae or Buteoninae include the remaining genera, 

 in which the edge of the bill is not toothed, though it may be 

 festooned. If the tibia and tarsus are about equal, we have 

 Accipiter or Astur, the former with the middle toe very long. The 

 Goshawk (Astur atricapillus) is slaty-blue above in the adult male, 

 with the crown almost black; but the young bird, more often seen 

 in Colorado, is dark brown above, the feathers of the head and 

 back largely edged with tawny, while there is an indistinct white 

 collar across the back of the neck. It is nearly always found in 

 winter in our State. A western subspecies (A. a. striatulus), 

 with darker colors, is reported from Garfield County. The two 

 species of Accipiter are among our common birds; the larger (wing 

 9 to 1 1 inches), with rounded tail, is Cooper's Hawk (A. cooperi); 

 the smaller (wing six to eight and one-half inches), with the tail even 

 or slightly notched, is the Sharp-shinned Hawk(^4. velox). Cooper's 

 Hawk is destructive to poultry, and is the one species which may 

 be regarded with disfavor. The next five genera have the tibia 

 longer than the tarsus. The kites have only the outer two pri- 

 maries emarginate on the inner web. The two species recorded, 

 representing the genera Elanoidcs and Ictinia, are rare stragglers. 

 In Circus and Butco three to five of the outer primaries are emar- 

 ginate. The Marsh Hawk (Circus cyaneus hudsonius) has a 

 rather owl-like face, more or less surrounded by a ruff; the wing 

 is 13^2 inches in the male, 1 5 inches the female. It is very common 

 in Colorado, particularly on the plains. Buteo, with which Archi- 

 buteo may be included as a subgenus, is represented by four 

 species, these including the common large hawks often seen flying 



