Eagle. RAPTORES. AQUILA. 13 



possession, and was obtained from the Highlands of Perth- 

 shire, 



In the brief Descriptions that accompanied the progressive 

 publication of the Engravings, I stated an opinion that the 

 Falco Chrysaetos and Falcofulvus of authors were distinct 

 species. 



In consequence of some doubts having arisen as to the cor- 

 rectness of this supposition, I was led, since that period, to 

 direct my attention particularly to the history of these birds ; 

 and the result of further examination has convinced me, that 

 the former opinion had been too hastily adopted. I now con- 

 cur with Mons. Temminck in considering them as individu- 

 als of the same species, at different periods of age : the Chry- 

 saetos denoting the adult ; the Fidviis the young, or imma- 

 ture bird. 



After the inspection of several specimens, and minute in- 

 quiry in those districts of Scotland where eagles abound, it 

 would seem that the white ring, which distinguishes the 

 F.J\dvus, is confined to birds of a certain age. During the 

 first year, the ring appears well defined, occupying the larger 

 and upper half of the tail ; but at the moult which takes 

 place subsequent to this age, the line between the white and 

 lower or dark part of the tail becomes interrupted, and a few 

 patches of a hair-brown colour make their appearance, ad- 

 vancing upon the white ring. 



At this age, and under this very state of feather, I had an 

 opportunity of examining two living specimens at Mar Lodge 

 in Aberdeenshire, which had been taken from the same nest 

 in the preceding year. Each succeeding change of feathers, 

 or moult, adds to the size of the brown patches, till the 

 bird has attained maturity (that is, its fourth year), when the 

 whole of the tail appears barred with hair and fZar/t-brown, 

 the roots of the feathers only remaining white ;» after which 

 it undergoes no further change. In the rest of their plum- 

 age, the difference between the young and adult bird is trif- 

 ling ; and in other essential characters, viz. the size and form 



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