232 WHITE-TAILED HAWK. 



considered them as identical, contrary to the opinion of Vieillot, whose 

 authority, it is true, could in this case be of little weight, as he had not 

 seen the species, but like many others had merely given it a name ; his 

 sole knowledge of it being derived from the work of d'Azara. We have 

 now yielded only to the decision of Temminck (who has lately intro- 

 duced the young into his Planches Coloriees), but not without much 

 reluctance, especially as that distinguished ornithologist has evidently 

 not been at the trouble of comparing the two species. Otherwise, he 

 would certainly not have omitted noticing their affinities and differential 

 characters ; since in the history of species so closely allied as these two, 

 the differential characters are of more importance and utility than the 

 most labored descriptions. 



This comparison we have carefully instituted between our American 

 specimens, and others from Africa and Java. They agreed perfectly, 

 especially with that from Java, in every, the minutest character, even 

 feather by feather, much better than birds of prey of the same species, 

 and from the same country, do generally. X^ey are even more alik<^ 

 than different specimens from the old continent of the Black-winged 

 itself, since that species is said to vary considerably in the black mark- 

 ings, which extend more or less on the wings in different individuals. 

 Nevertheless, a constant, though trivial, differential character, added to 

 the difference of locality, has induced us to follow Temminck's course, 

 in which we should never have ventured to take the lead. This charac- 

 ter consists in the tail being in Falco dispar constantly irregular, while 

 in F. melanopterus it is even ; or to explain it more clearly, the outer 

 tail-feather is rather the longest in the African, and more than half an 

 inch shorter than the next in the American species. This essential 

 character is much more conspicuous in Temminck's plate than in ours, 

 owing to the tail being spread. In the Black-winged_also, the lower 

 wing-coverts are destitute of the black patch so conspicuous in the 

 American bii'd ; a female from Java has, however, a slight indication 

 of it, but no trace of it is observable in our African males. 



By admitting this to be a distinct species from the Black-winged 

 Hawk, we reject one more of those supposed instances, always rare, 

 and daily diminishing upon more critical observation, of a common 

 habitation of the same bird in the warm parts of both continents, with- 

 out an extensive range also to the North. A steady and long protracted 

 exertion of its powerful wings, would- have been requisite to enable it to 

 pass the vast and trackless sea which lies between the western coast of 

 Africa, the native country of the Black-winged Hawk, and the eastern 

 shores of South America. Yet were the species identical, this adven- 



these already numerous synonyms, Falco axillaris, Lath. Ind. Suppl. [Circus axil- 

 laris, Weill. \) from New Holland. 



