Our Birds of Prey. 139 
changes which render it almost impossible to declare what 
tints one might meet with at different ages. The 
changes may take place either completely all over the 
bird, or only partially. 
In L. uncinatus the length of body is about 17 inches 
and the young birds are brown, with reddish or yel- 
lowish edges to many of the feathers, the wings and 
tail being barred with the same tints. The head is 
of a deep brown, while a collar round the neck, and 
the under surfaces, are white, more or less spotted 
or barred with brown, or reddish brown. Gradually 
these tints give place to darker or paler shades. The 
brown becomes nearly black and then grey or slaty 
or dark blue, the head and neck especially; the collar 
round the neck becomes pure white, changing to grey 
and dark reddish and yellowish brown, and then 
altogether disappears ; the bars on the wings become 
less numerous and less conspicuous above — those on 
the tail being replaced by two broad pairs, black and 
slaty-grey alternating ; while the under surface changes 
from white to yellowish, and then to reddish or chest- 
nut, blotched or barred with one or more of the same 
tints on a lighter ground, and then eventually to an 
irregular barring of blue and grey or white. 
In L. cayennensis, the size of which is much greater 
than in the preceding — the females especially — the 
changes are less extreme, so far as the under surface is 
concerned, where the ground tint is always white, either 
pure or creamy, or blotched and streaked with brown ; 
but on the upper surface, the changes are even more 
striking, for the brown tint of the young becomes more 
and more broadly edged with whitish brown and reddish 
R2 
