154 Field Museum of Natural History- — Zoology, Vol. IX. 



Ik'ad, nock and entire under parts, pure \vliitc; rest of plumage, 

 glossy bluish black; wing, less than 19; primaries, dark slaty, show- 

 ing greenish tinge when held in the light ; two outer primaries, notched ; 

 tail, long and forked. Elanoidcs forficatus. 



Swallow-tailed Kite. 

 See No. 151. 



Wing, always over 18.50; belly and thighs, never white; only 

 adult birds have the hood and tail white. Halicretus leiicoccphalus. 



Bald Eagle. 

 See No. 166. 



SECTION 3. Fourth primary, longest; tarsus, partly (not entirely) 



feathered. 



Tail, rufous brown (adult); tail, whitish or grayish, with numer- 

 ous brown bars (immature). Buteo borealis, and races. 



Red-tailed Hawk. 

 See Nos. 158, 158a, 158b, 158c. 



General plumage, dark sooty brown, sometimes with pale under 

 parts, more or less streaked and spotted. Buteo borealis harlani. 



Harlan's Hawk. 

 See No. 158c. 



Wing, always over 18.50; only adults have head and tail white. 



HalicBetus leucocephalus. 

 Bald Eagle. 

 See No. 166. 



SECTION 4, Fourth primary, longest; tarsus, entirely feathered. 



Thighs, tawny, more or less streaked or barred. 



Archihuteo lagopus sancti-johannis . 

 American Rough-legged Hawk. 



See No. 164. 



General plumage, sooty brown or black (black plumage). 



Archihuteo lagopus sancti-johannis . 

 American Rough-legged Hawk. 

 See No. 164. 



