TAcuLes. RAPACES. FALCO. 5 
the former opinion had been too hastily adopted. I now concur Identity of 
‘ ; : 3 eee Falco 
with Mons. Trmmincx in considering them as individuals of Chrysastos 
the same species, at different periods of age: the Chrysaétos a F. ful- 
denoting the adult; the Fulvus the young, or immature ~ 
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. fulvus, 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, Variation 
or moult, adds to the size of the brown patches, till the chuieee 
bird has attained maturity (that is, its fourth year), when the young to 
: é ; the adult. 
whole of the tail appears barred with hair and dark-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 
of the bill, the number of scales upon the feet, and anatomi- 
cal structure, they appear perfectly similar *. 
* According to Mr Bullock, both the Fulvus and Chrysaétos breed in the 
Orkneys. I do not mean to doubt the assertion, so far as supposition ex- 
tends; but may not the mere separation of residence that takes place be- 
tween the adult birds, and those yet in an immature state, lead cursory 
observers to think that the process of incubation, &c. is going on in both 
situations? If such is the fact, and they are the same species, it would 
appear that the imperfect state of plumage, in their progress to the adult 
bird, does not retard maturity, with respect to propagation; though we 
might look for such an effect, from knowing that many species of the ge- 
