94 



BRITISH BIRDS. 



and has not the head and neck so lightly coloured. In young birds the 

 beak is black, the cere darker than in adults, the irides brown, and the 

 whole plamage more uniform in colour and much darker ; the tail-feathers, 

 too, are dark brown, not becoming purely white until the bird is some six 

 or seven years old. In this stage of plumage it is the Aquila ossifragus of 

 some authors. 



Varieties of this bird sometimes occur. Meyer figures, in his ' British 

 Birds/ a specimen taken in Ireland, which has the whole of the plumage a 

 uniform bluish-grey colour. Gray, in his ' Birds of the West of Scotland/ 

 mentions a specimen in the possession of Sir James Mathesoii, Bart., of 

 Stornoway Castle, very bright in colour (a uniform yellowish grey) and of 

 extraordinary size. Mr. St. John records a specimen pure silvery white, 

 another albino specimen being also in the museum at Dunrobin Castle. 

 Great differences of size are also to be observed in this species, its alar 

 extent varying from six to seven, and even seven and a half feet. 



