BIRDS OF NORTH AND MIDDLE AMERICA 223 



kk. Tail not whitish or very pale tawny, but grayish or 

 grayish brown. 

 I. Body entirely blackish (west and central North 



America) B. harlani, jviv. (p. 268) 



B. jamaicensis calurus, black phase, ju v. (p. 246j'* 

 II. Body not entirely blackish. 



m. Upperparts with very much white mottling 

 (western Canada to Mexico and Louisiana). 

 B. jamaicensis kriderii, juv, (p. 257) 

 mm. Upperparts with relatiyely little white mottling 

 and considerable tawny mottling, 

 n. Size smaller; wing, cf usually under 355 mm., ? 

 under 370 mm. 

 0. Pale interspaces of rectrices paler; very 

 distinctly lighter than the dark bars and 

 with a slight rufous wash (Jamaica, His- 

 paniola, Virgin Islands) 

 B. jamaicensis jamaicensis, juv. (p. 262) 

 00. Pale interspaces of rectrices darker; not very 

 distinctly lighter than the dark bars, and 

 with no rufous wash (southeastern Alaska 

 to Queen Charlotte Islands). 

 B. jamaicensis alascensis, juv. (p. 256) 

 nn. Size larger; wings, d' usuallj' over 355 mm.; 9 

 over 370 mm. 

 0, Thighs heavily spotted or barred (western 

 North America). 

 B. jamaicensis calurus, light phase, juv. (p. 246). 

 B. jamaicensis fuertesi, juv. (p. 255) 

 00. Thighs usually unmarked, or if marked, 

 narrowly and sparsely barred. 



B. jamaicensis borealis, juv. (p. 239) 

 B. jamaicensis umbrinus, juv. (p. 260) 

 B. jamaicensis solitudinis, juv. (p. 261) 

 cc. Tail less than half as long as wing. 



d. Tail slightly less than half as long as wing, square or only slightly 

 rounded; three outer primaries incised on their inner webs. 

 e. Lower breast, abdomen, thighs, and flanks white, sometimes faintly 

 barred with dusky. 

 /. Size large; wings, c? 430 mm., 9 440-475 mm. 



B. albicaudatus albicaudatus, ad. (extralimital)" 



>8 I know of no certain way of distinguishing between these two in this plumage. 

 Usually harlani is purer black, less brownish, than calurus, but this condition is 

 not constant. 



" Buteo albicaudatus Vieillot, Nouv. Diet. Hist. Nat., iv, 1816, 477 (South 

 America=Rio de Janeiro apud Berlepsch, Nov. Zool., xv, 1908, 291). — Buteo 

 albicaudatus albicaudatus Peters, Check-list Birds of World, i, 1931, 229. 



