48 



Resembling B. borealis calurus, but smaller 

 throughout ; wing (^ ad. 344 mm. ; $ 365 

 mm. ; dark areas blacker and more extended. 

 142d. Buteo borealis alascensis Grinnell, Univ. Cal. S. E. Alaska. 

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

 Bay and Chichagof /.] 

 Alaska Red-tail. 



Tail uniform rufous, with one very narrow 

 sub-terminal band ; flanks and thighs light 

 rufous ; juv., tail barred, and flanks and thighs 

 sparsely barred with rufous. 

 142e. Buteo borealis costaricensis Ridgw., Hist. N. Costa Rica to 

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



Central American Red-tail. 



Size of B. borealis borealis, but darker above ; 

 throat and middle of belly with broad con- 

 spicuous striping and banding of deep 

 chocolate brown ; tail feathers with dark 

 brown markings (remains of bands) near 

 shaft. 

 142f . Buteo borealis umbrinus Bangs, Pr. New Engl. Florida, 

 Zool., CI. ii., p. 67 (1901). [Myakka, Bahamas. 

 Manatee Co., Florida.] 

 Florida Red-tail. 



Socorro 

 Island. 



Tres Marias 

 Islands. 



Small form : wing ^ 14.94-15.70, $ 16.76 in. 

 Insular race, undescribed ? * 

 142g. Buteo borealis socorroensis Ridgw., Pr. U.S.N. 

 Mus., iii., 1880, p. 220 (1881) [Socorro /.] 

 [nom. nudem.] 

 Socorro Island Red -tail. 



More rufous on sides of breast and belly ; 

 thighs heavily barred with brown. 

 142h. Buteo borealis fumosus Nelson, Pr. Biol. 



Soc. Wash. xii. p. 7 (1898) [Tres Marias 



Is.] 



Tres Marias Red-tail. 



Length 21, wing 14.50 in. ; above sooty- 

 brownish with purplish gloss and ferruginous 

 edgings ; tail rusty ferruginous, base and tips 

 white with sub-terminal dusky-black band 

 and 7-9 dusky bars ; wing quills rich brown, 

 barred with black ; below white tinged 



* The example in Tring Mus. is black with rufous tail, having broad 

 sub-terminal band, and 8 or 9 narrow obsolete bars, presumably' a melanism. 



