78 



strongly marked and rufous below, especi- 

 ally on thighs, and with more bars than 

 the sub-terminal one on tail; melanisms 

 are frequent, but they usually retain the 

 rufous tail.^ 



tl43d. Buteo borealis harlani^ (Aud.), Bds. Am., i.. Lower 



pi. 86 (1830). {Near St. Francisville, Mississippi 

 Louisiana, type in Brit. Mus.] Valley & Gulf 



Harlan's Hawk. States, from 



Texas and 

 Dark phase : resembling a melanism of Louisiana to 

 B. borealis krideri ; wing ^ 380, ? 400- Florida. 

 408 mm. ; nearly uniform sooty-brownish- 

 black, with much less of concealed white ; 

 tail mottled with greyish, dusky and rufous, 

 with sub-terminal black band. Light 

 phase : resembling a small darker example 

 of B. b. borealis. 



143e. Buteo borealis alascensis Grinnell, Univ. Cal. 

 Pub. Zool., v.. No. 2, p. 211 (1909). [Glacier 

 Bay and Chichagof I.} 

 Alaska Red-tail. 



S.E. Alaska. 



Resembling B. botealis calurus, but smaller 

 throughout ; wing ^ 344-355 mm. ; ? 365- 

 370 mm. ; dark areas blacker and more 

 extended. 



143f. Buteo borealis costaricensis Ridg., Hist. N. 

 Am. Bds., iii., p. 285 (1874). [Costa Rica.] 

 Central American Red-tail. 



Guatemala and 

 Costa Rica to 

 Panama. 



1 I have examined the type of B. cooperi Cassia in the U.S. Nat. Mus. and am 

 obliged to conclude it is an aberrant example of this form. 



' Even after examination of a number of available specimens in the United 

 States I am unable to discard this form as a melanism, since it seems to cover a 

 definite geographical area and to be smaller than B. b. borealis. Light birds, such 

 as those from Florida, with the rufous tail of B. borealis borealis, undoubtedly occur 

 in its area, but they equal it in size. Melanistic birds referrable to harlani occur in 

 Canada, Mr. Taverner assures me, within the range of krideri ; yet it is impossible 

 to throw the range of harlani into that of krideri. 



