




























236 Mr. J. H. Gurney’s Notes on 
With reference to this question, it may be interesting to 
quote the opinion of Dr. Elliott Coues, as expressed at p. 357 
of his recent work on the Birds of the North-west. Dr. 
Coues there remarks :—“ This dark plumage is an individual 
peculiarity, not a normal stage of regular occurrence.” 
The remaining American species of the genus Buteo may, 
I think, be regarded as belonging to the central group of 
that genus, of which B. vulgaris is the type; and in con- 
sidering these, I propose first to refer to Buteo borealis and 
its western representative, to which. Mr. Sharpe assigns the 
subspecific name of “montanus.’ With reference to this 
appellation, Messrs. Baird, Brewer, and Ridgway write thus 
in vol, il. of the ‘ Land Birds of North America,’ p. 288 :— 
“It being certain that the Buteo montanus of Nuttall is 
really the B. swainsoni, and not the variety of borealis so 
called by Mr. Cassin, it becomes necessary to drop the name 
in connexion with the present bird, and transfer it as a 
synonym to swainsoni. In its place Mr. Cassin’s name 
calurus must be substituted, under which was described the 
melanistic condition of the present variety of B. borealis.” 
It would therefore appear that Buteo montanus of Mr. 
Sharpe’s work should rather bear the name of B. calurus. 
To define with precision the distinction between the true 
B. borealis of North-eastern America and its darker and 
more ferruginous western congener, B. calurus, is a difficult 
and, I suspect, an impossible task ; for, great as is the differ- 
ence in coloration between typical examples of the two races, 
intermediate gradations occur which it is hardly possible to 
divide by any satisfactory line of demarkation. 
Mr. Sharpe, in his article upon B. calurus, speaks of the 
“western birds” as being “ much larger, more powerful, and 
darker-plumaged than the eastern, or ordinary specimens of 
B. borealis.” | 7 
This observation. is undoubtedly correct as to the darker 
plumage in the great majority of western specimens, but, 
according to the measurements supplied by Messrs. Baird, 
Brewer, and Ridgway, can hardly be said to hold good as 
regards the alleged larger size of B. calurus. 



