188 Birds of Colorado 



But few details have been noted about its nesting-habits 

 in Colorado, except that it makes use of crevices and ledges 

 in high cliflfs and cailon walls. Some notes by Gale, 

 quoted by Bendire and Cooke for this species, refer, 

 according to Gale's notebook, to the Mexican Falcon, 

 and not to this species. The eggs are deposited about 

 the middle or end of April on a bare ledge, with little 

 or no nest. They are three or four in number, and are 

 generally short, rounded and ovate. They vary consider- 

 ably in colour and markings, the ground-colour, when 

 visible, being creamy-white, sometimes blotched and 

 streaked, sometimes entirely overlaid, with reddish and 

 sepia browns. In size they average 2'1 x 1*6. 



Pigeon- Hawk. Falco columharius. 



A.O.U. Checklist no. 357 — Colorado Records — Ridg-nay 73, p. 186 ; 

 Drew, 85, p. 17 ; Morrison 88, p. 115 ; 89, p. 65 ; Kellogg 90, p. 87 ; 

 Fisher 93, p. 109 ; Lowe 94, p. 267 ; McGregor 97, p. 38 ; Cooke 97, 

 p. 76 ; Rockwell 08, p. 163. 



Description. — Adult Male — Above bluish-slate, most of the feathers 

 with a black shaft-line ; quills dusky, with white spots along the inner 

 webs only ; tail like the back, with four transverse black bands more 

 or less completely developed, the terminal one mvich broader than the 

 others and tipped with white ; below white, washed with tawny 

 jX)steriorly, the throat plain, the rest longitudinally streaked with 

 sepia-brown ; sides of the face bluish and streaked ; iris brown, bill 

 bluish-black, base and cere yellowish, legs yellow. Length ll-S ; 

 wing 7-7 ; tail 4-5 ; cubnen "55 ; tarsus 1'4. 



The female is dusky brown above, and the tail is like the back, but 

 crossed by four narrow, sometimes nearly obsolete, whitish bands 

 the uppermost often concealed by the coverts ; below as in the male, 

 but often more fulvous and the streaking heavier ; wing 8*5. Young 

 birds resemble the female, and this is the plumage most generally 

 met with, as adult males are not often seen. 



Distribution. — The whole of North America, breeding chiefly north 

 of the United States, but south of the boimdary along the higher 

 elevations of the Cascades, Rockies and AUeghanies ; south in winter 

 to the West Indies and northern South America. 



In Colorado the Pigeon-Hawk is by no means a common bird, and is 

 chiefly met with on migration, though a few birds remain to breed in the 



