so 
FALCO LEUCOCEPHALUS. 
The white-headed eagle is three feet long 1 , and seven 
feet in extent ; the hill is of a rich yellow ; cere the same, 
slightly tinged with green ; mouth, flesh-coloured, tip 
of the tongue, bluish black; the head, chief part of the 
neck, vent, tail coverts, and tail, are white in the perfect, 
or old birds of both sexes, — in those under three years 
of age these parts are of a gray brown ; the rest of the 
plumage is deep dark brown, each feather tipt with pale 
brown, lightest on the shoulder of the wing, and darkest 
towards its extremities. The conformation of the Aving 
is admirably adapted for the support of so large a bird ; 
it measures two feet in breadth on the greater quills, 
and sixteen inches on the lesser ; the longest primaries 
are twenty inches in length, and upwards of one inch 
in circumference where they enter the skin ; the broadest 
secondaries are three inches in breadth across the vane; 
the scapulars are very large and broad, spreading from 
the back to the wing, to prevent the air from passing 
through ; another range of broad flat feathers, from three 
to ten inches in length, also extend from the lower part 
of the breast to the wing below, for the same purpose ; 
between these lies a deep triangular cavity ; the thighs 
are remarkably thick, strong, and muscular, covered with 
long feathers pointing backwards, usually called the 
femoral feathers ; the legs, which are covered half way 
below the knee, before, with dark brown downy feathers, 
are of a rich yellow, the colour of ripe Indian corn ; 
feet the same ; claws, blue black, very large arid strong, 
particularly the inner one, which is considerably the 
largest; soles, very rough and warty ; the eye is sunk 
under a bony, or cartilaginous projection, of a pale yello w 
colour, and is turned considerably forwards, not standing 
parallel with the cheeks, the iris is of a bright straw 
colour, pupil black. 
The male is generally two or three inches shorter than 
the female ; the white on the head, neck, and tail being 
more tinged with yellowish, and its whole appearance 
less formidable ; the brown plumage is also lighter, and 
the bird itself less daring than the female, — a circum- 
stance common to almost all birds of prey. 
