LAND BIRDS. 267 
lasted several days and appears to take place late in August and early in 
September every year. 
TECHNICAL DESCRIPTION. 
Adult male: Uniform dark bluish gray or slate blue above, the feathers of the occiput 
pure white beneath the surface; under parts white, the throat narrowly streaked and the 
rest heavily barred with reddish brown; primaries blackish on outer webs, bluish white 
barred with black on inner webs, the five outer ones emarginate on the inner webs; tail 
colored like the back, but with about five blackish cross-bars, the tip narrowly white. 
Tail square or slightly emarginate at tip; bill black; legs and feet yellow; iris reddish brown. 
Length 10 to 11.50 inches; wing 6.10 to 7.10; tail 5.80 to 6.10. Adult female: Similar 
in color to the male, but decidedly larger. Length 12.50 to 14 inches; wing 7.80 to 8.80; 
tail 6.60 to 8.20. Immature: Without any slate blue, the upper parts brownish, the 
feathers mostly edged with rufous and the tertiaries and scapulars with many partly 
concealed, large, white spots; under parts white, everywhere streaked with pale brown, 
many feathers with sharp shaft lines of dark brown or blackish. 
136. Cooper’s Hawk. Accipiter cooperi (Bonap.). (333) 
Synonyms: Pigeon Hawk, Chicken Hawk, Quail Hawk, Blue Darter, Swift Hawk.— 
Falco cooperii, Bonap., 1828.—Accipiter cooperi, Gray, 1844, and authors generally.— 
Astur cooperi, Jard., DelkXay, and some others.—Nisus cooperi, B. B. & R., 1875. 
Fig. 70. Cooper’s Hawk. Adult. 
From Baird, Brewer & Ridgway’s North American Birds. Little, Brown & Co. 
Figures 70 and 71. 
With nearly the same proportions as the Sharp-shinned Hawk, but 
averaging decidedly larger, with heavier legs and feet, and the tail rounded 
instead of square. In coloration the two are very similar, and there is the 
same general difference between adults and immature birds. — 
Distribution.—North America from southern British America south to 
southern Mexico. Breeds throughout its range. 
Probably, all things considered, our most abundant hawk. It is found 
in all parts of the state, and in all seasons of the year, except during two or 
three of the coldest months. It nests everywhere throughout the state, 
