AVES FALCONID/E. 



659 



Bill orange-yellow at base, shading into clear blue horn ; cere orange- 

 yellow. 



Fig. 337. 



Foot of Fa/co cassini ; adult female, P. U. O. C. 7902. From the side; natural size. 



Feet orange-yellow ; the claws bluish black. 



Iris dark hazel-brown. 



The adult female cited above is colored like the bird just described ; 

 there is a stronger tendency to cream and buffy shades on the lower surface 

 and the barring is stronger and less broken by sagittation on the feathers. 



Young birds of the year and till they assume full plumage are very dif- 

 ferent in color from the adults and also appear to average a little larger 

 in size. 



Head : Forehead and feathers in front of eye whitish ; crown deep 

 blackish brown, the feathers more or less margined with chocolate or dull 

 chestnut; feathers under the eye, the sides of the face, and a moustachial 

 streak, not so wide as in the adult, deep black ; ear-coverts shaded with 

 buffy or chestnut. 



