aA: KEY TO THE BIRDS OF EASTERN NORTH AMERICA. 
Section 7. Fourth primary, longest; four or five outer 
primaries, emarginate or notched; tarsus, entirely 
feathered ; upper tail coverts, not white. 
Thighs, tawny, more or jess streaked of barred 
American Rough-legged Hawk. 
Archibuteo lagopus sancti-johannis. 
See No. 281. 
General plumage, sooty brown or black (black plumage). 
American Rough-legged Hawk. 
Archibuteo lagopus sancti-johannis. 
See No. 281. 
Thighs, tinged with deep rufous with numerous bars. 
Ferruginous Rough-legged Hawk. 
Archibuteo ferrugineus. 
See No. 282. 
Section 8. Fourth primary, longest; three outer primaries, 
emarginate or notched. 
Tarsus, partly feathered; throat, white (adult) ; throat, tawny or buff (immature). 
Swainson’s Hawk. 
Buteo swainsont. 
See No. 277. 
Group 6. Wing, 17 to 21 inches long. 
Section 1. Third primary, longest; tarsus, wholly 
feathered. 
Basal portion of inner web of primaries, largely white, without bars; thighs, 
tawny or butt, more or less barred ; tarsus, thickly feathered. 
American Rough-legged Hawk. 
Archibuteo lagopus sancti-johannis. 
See No. 281. 
Basal portion of inner web of primaries, largely white, without bars; thighs, 
tinged with deep rufous heavily barred. 
Ferruginous Rough-legged Hawk. 
Archibuteo ferrugineus. 
See No. 282. 
