170 Birds of Colorado 
sometimes almost unmarked, and sometimes so heavily 
blotched as to conceal the ground-colour. They average 
1-4 x 1:2. Gale gives the usual date for eggs June 
10th to July 10th; the latter at 11,000 feet elevation 
in Boulder co. 
Cooper’s Hawk. <Accipiter coopert. 
A.O.U. Checklist no 333—Colorado Records—Drew, 81, p. 141; 
85, p. 17; Allen & Brewster, 83, p. 197 ; Morrison 88, p. 115; 89, p. 7; 
Bendire 92, p. 192 ; Lowe 94, p. 267 ; Cooke 97, pp. 74, 204; Henderson 
03, p. 235; 09, p. 229; Gilman 07, p. 154; Rockwell 08, p. 162; 
Warren 09, p. 14. 
Description.—Closely resembling A. veloz in plumage, but much larger 
with the crown a distinctly darker slate than the back, the tail more 
strongly white-tipped and rounded, not square. Length 16-5; wing 
9.1; tail 7-2; culmen -8; tarsus 2-4. The female is larger—wing 10.0, 
tail 8-25. The young bird bears u rather close resemblance to the 
young Goshawk (Astur airicapillus), but it is smaller and can be at 
once distinguished by the generic character of the long middle toe. 
Distribution.— Breeding from the St. Lawrence Valley and British 
Columbia south to southern Mexico ; a migrant north, a resident south 
of about 40°. 
Cooper’s Hawk is a fairly common bird in Colorado, and generally 
distributed, breeding from the plains to about 9,000 feet. It is stated 
to be a resident and probably is so to a certain extent in the south, 
though I have found no winter records, nor is it included in Gale’s list 
of birds wintering in Boulder co. It is undoubtedly more abundant 
in the summer. 
The following are localities: Boulder co., breeding in the mountains 
(Gale) ; Middle Park, breeding (Carter) ; El Paso co., April to September 
(Aiken coll.) ; Salida, May (Frey) ; Wet Mountains, to 8,000 feet (Lowe) ; 
Mesa cc., once in March (Rockwell) ; Naturita Cafion, April (Warren) ; 
La Plata co., breeding (Morrison). 
Habits.—Cooper’s Hawk is generally met with about 
moderately open country and cultivated districts. It is 
in every respect a larger edition of the Sharp-shinned : 
equally audacious and rapacious, but in Colorado far 
less common. Its flight is ordinarily not swift, but 
when in pursuit of its prey it has a wonderful power 
of twisting and doubling. It is very destructive to 
