154 PROCEEDINGS OF UiNITED STATES NATIONAL MUSEUM. 



143. Circus hudsonius; (Liun.) 



Probably tbe most commou species of Hawk diiriDg tbe winter 

 mouths, arriving in September and leaving in April. A large propor- 

 tion are in immature plumage. — (Dresser, Ibis, 1865, 328. — G. cyaneits 

 hudsonius, Sennett, B. Rio Grande, 40.) 



144. Nisus fuscus, (Guiel.) 



Found sparingly in winter. — [Accipiter /., Dresser, Ibis, 1865, 324.) 



145. Nisus cooperi, (Bou.) 



Like tbe last. — {Accipiter c. Dresser, Ibis, 1865, 323. — Sennett, B. 

 Rio Grande, 42.) 



146. Anteuor unicinctus var. harrisi, (Aud.) 



Resident and quite abundant. In its habits, this bird resembles thie 

 Caracara E;igle, but is not so active. The nests are hardly distinguish- 

 able in situation or construction, and the two eggs are also deposited 

 at an interval of three or four days. Six eggs average 2.08 by 1.62 j 

 they are dull bluish or yellowish white, faintly stained with yellowish- 

 brown. — [Graxirex unicinctus, Dresser, Ibis, 1865, 329.— Bwfeo unicinc- 

 tus harrisi, Sennett, B. Rio Grande, 42.) 



147. Buteopennsylvanicus, (Wils.) 



Uncommon winter visitor. — (Dresser, Ibis, 1865, 325. — Sennett, B. 

 Rio Grande, 43.) 



148. Buteo swainsoni, Bon. 



Occurs sparingly in winter. — (Dresser, Ibis, 1865,324.) 



149. Buteo borealis, (Grnel.) 



A pair seen January 10, 1877, near Fort Brown, seemed to approach 

 var. hrideri in the extent and purity of white beneath, although the 

 subterminal band of black on the tail was very distinct. The birds 

 sailed several times quite near me, and I had a very good view of 

 them. — (Dresser, Ibis, 1865, 324.) 



150. Buteo harlani, Aud. 



Early in November, 1876,1 observed a single specimen of this species 

 sailing in easy circles at no great distance from the ground; but, not 

 having my gun, I was unable to secure it. — (Dresser, Ibis, 1865, 324.) 



151. Buteo albicaudatus. — The Wliite-tailed Buzzard. 



Aquila coUhlaiua, Azara, Apuut. 1, 1803,69. 



Buteo albicaudat lis, YiEU.L.,'Ni>nv. Diet. IV, 1810, 477 (f.f Azaka, I.e.). — Strickl., 

 Orn. Syii. 1, 1855, 35.— Salvin, P. Z. S. 1870, 215 (Veragua). 



Tachytriorchis albicaudatus, Sharpe, Cat. Ace. Brit. Mu8. I, 1874, 162. 



Craxirex albicaudatus, RiDc.w., Pr. Ac. Nat. Sci. Pliila. 1875, 92. 



Buteo {Craxirex) albicaudatus, RiDGW.. t. c. 98 (luouographic). 

 Spizaetus leucurus, Vieill., Nonv. Diet. XXXII, 1819,59. 



Buteo leucurus, L.wn., Rev. Zoo). 1849, 100. 



