146 FIELD MUSEUM OF NATURAL HISTORY ZOOLOGY, VOL. IX. 



Rump and upper tail coverts, dark brown; breast, streaked with 

 dark brown; no rufous brown on tail; second primary, longest 

 (immature); back and rump, slate color (adult). 



Falco columbarius, and races. 

 Pigeon Hawk. 

 See Nos. 170, iyoa. 



GROUP 2. Wing, 8.50 to 9.50 inches long. 



Second primary, longest. Falco columbarius, and races. 



Pigeon Hawk. 

 See Nos. 170, i7oa. 



Fourth primary, longest; outer tail feather, three-quarters inch 

 or more shorter than middle feather; tail, usually more than 7.25 

 long. Accipiter cooperii. 



Cooper's Hawk. 

 See No. 156. 



Sharp-shinned Hawk. 



Fourth primary, longest; outer tail feather, less than three-quar- 

 ter inch shorter than middle feather; tail, usually less than 7.25 long. 



Accipiter velox. 

 Sharp-shinned Hawk. 

 See No. 155. 



