AVES FALCONID/E. 



561 



and sides, as well as the thighs, dark seal-brown, narrowly barred with 

 whitish, or isabeline ; the under tail-coverts have the white areas predom- 

 inating, so as to be in the main light, narrowly barred with dark seal- 

 brown. 



Bill : Dark horn-blue ; cere and bare skin about eye carmine-red, or 

 yellow of greater or less brilliancy according to season. 



Iris: Deep hazel-brown. Crop-patch yellow. 



Feet: Yellow. 



FIG. 281. 



Polyborvs plancus. Immature female. About one-fifth natural size. 



Immature Birds. Head : Brown patch dull brown, with intermixture of 

 rufous and buflfy shading ; this crown-patch reaches from the base of the 

 bill backward above the eyes and is not as well defined as in the adult ; 

 the region in front of the eye unfeathered and with many scattered 

 bristling hairs, almost black in color; sides of the head and face tawny 

 buff. 



Neck : Tawny buff below and brown of a rusty dull shade with tawny 

 buff in the center of each feather, often taking the form of an irregular 

 median stripe. 



Back: Interscapular region, upper and mid-back of dull brown, each 

 feather streaked medianly with dull buff, widening to form a tip of that 

 color, irregular in shape at the terminus ; lower back pale ashy brown, the 

 feathers obsoletely barred and marked with dirty white ; rump dirty white, 

 the feathers barred irregularly with pale ashy brown ; upper tail-coverts 

 dirty white, without barring, except at the base of some of the coverts closest 

 to the rump. 



