170 Birds of Colorado 



sonaetimes 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 cooperi. 



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. 2G7 ; 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. velox in plumage, but much larger 

 with the crown a distinctly darker slate than the back, the tail more 

 strongly white-tipped and rounded, not sciuare. Length 16-5 ; wing 

 9-1; tail 7-2; cuhnen .8; tarsus 2-4. The female is larger — wing 10-0, 

 tail 8»25. The young bird bears a rather close resemblance to the 

 young Goshawk {Astur atricapilhis), 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 fairlj' 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 siunmer. 



The following are locahties : Boulder co., breeding in the mountains 

 (Gale) ; Middle Park, breeding (Carter) ; El Paso co.,AiDril to September 

 (Aiken coll.) ; Salida, May (Frey) ; Wet Mountains, to 8,000 feet (Lowe) ; 

 Mesa CO., once in March (Rockwell) ; Naturita Canon, April (Warren) ; 

 La Plata co., breeding (Morrison). 



Habits. — Cooper's Hawk is generally met wdth 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 



