78 



strcjiigly marked and rufous below, especi- 

 ally on thighs, and with more bars than 

 the sub-terminal one on tail ; mclanisms 

 arc frequent, but they usually retain the 



rnf( 



tail.i 



^143d. Jiitlcii burcalis luirlaiii- (Aud.j, Bds. Am., i.. Lower 



pi. 86 (1830). [Near St. fni7icisville, Mississippi 

 Louisiana, type in Brit. !\Ius. | Vallt-y & Gulf 



Harlan's Hawk. States, from 



Texas and 

 Dark ])liase : resembling a melanism of Louisiana to 

 B. boiralis krideri \ wing S 380, $ 400- IHorida. 

 408 mm. ; nearly uniform sooty-brownisli- 

 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. boi'calis. 



143e. Bidco boreal is alasceiisis (irinncU, Univ. Cal. 

 Pub. Zool., v., No. 2, p. 21 1 (1909). [Glacier 

 Bay and Cliicliagof 1 . \ 

 Alaska Red-tail. 



S.E. Alaska. 



Resembling B. boiealis caliints, but smaller 

 throughout ; wing ^ 344-355 mm. ; 1 365- 

 370 mm. ; dark areas blacker and niore 

 extended. 



143f. Bideo borealis costaricensis Ridg., Hi>t. X. Guatemala and 

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

 Central American Red-tail. Panama. 



^ I have cxiimiiicd the type of B. coopcri Cassin in the U.S. Xat. .Miis. and am 

 obliged to conchide it is -aw aberrant e.xample of this form. 



* Even after e.xamination of a number of avaihible specimens in the United 

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

 definite geographical area and to be smaller than li. h. borealis. I-ight birds, such 

 as those from I'lorida, 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 /fr/rfrr/ ; yet it is impossible 

 t(} throw the range of harlani into that of krideri. 



