194 FALCONS, HAWKS, EAGLES, ETC. 



a*. Back fuscous, fourth primary longest, outer tail-feathers half an 

 inch or more shorter than the middle ones ; wing over 9-00. 



. 333. COOPER'S HA.WK. 

 b. Wing over 10-00. 



6. Second primary longest, tail generally over 9-00. 

 6. " Lower tail-coverts immaculate white." 353. WHITE GYRFALCON. 

 b*. " Lower tail-coverts always more or less marked with dusky." 



854. GRAY GYRFALCON and Kuces. 

 o>. Second primary longest, tail under 9-00. 



c*. Tarsus shorter than middle toe without nail, upper parts blackish. 



856. DUCK HAWK. 

 <*. Tarsus longer than middle toe without nail, upper parts 



brownish 355. PRAIRIE FALCON. 



d 1 . Third or fourth primary longest. 



d*. Cpper tail-coverts white 331. MARSH HAWK. 



d*. Upper tail-coverts brownish . . .834. AM. GOSHAWK (Im.). 

 . Outer primary generally one color, base sometimes whitish or with 

 a few imperfect bars. 



a. Tarsus entirely bare, scales on its front large, rounded. 



862. AUDUBON'S CARACARA. 



b. Tarsus entirely feathered .... MS. Yn*oenrov BoueB-LM, 



c. Tarsus partly feathered, scales on its front small, rounded. 



3G4. AM. OM-RKY. 



d. Tarsus partly feathered, scales on its front transverse, more or less 



Bquarr. 

 d 1 . Three outer primaries emarginate or " notched."* 



<f>. Wing under 12-00 .... 343. BROAD-WINCIED HAWK (Im.). 



d*. Wing over 12-00 342. SWAIXSON'S HAWK (Im.). 



'. Four outer primaries emarginate or u notched.'''' + 



*. Upper tail-coverts pure white 331. MARSH HAWK. 



*. Upper tail-coverts not pure white; wing under 13-50; Ic.sst-r 

 wing-coverts conspicuously margined with rufous. 



339. RED-BHOULDERED HAWK (Im.). 



e*. Upper tail-coverts not pure white; wing over 13-50; lesser wiii^- 

 coverts not conspicuously margined with rufous. 



337. RED-TAILED HAWK AND RACES. 

 2. Feathers of under parts with more or less numerous 



cross-bars. 

 A, Scales on front of the tarsus numerous, rounded. 



a. Wing under 15-00 856. DUCK HAWK. 



b. Wing over 15-00 362. AUDUBON'S CARACARA. 



. Scales on front of the tarsus sharply denned, transverse, more or less 



square. 



a. Four or five outer primaries cmarpinate or " notched." f 

 a. Tail white at the base and tipped with whitish. 



830. EVERGLADE KITE. 



* See Fig. 70. t See Fig. 09. 



