298 ZOOLOGICAL GARDENS. 



The essential characters of the genus Polyborus 

 consist in a beak, somewhat elongated, compressed 

 laterally, of considerable depth, strongly hooked at the 

 tip of the upper mandible, and covered at its base by a 

 hispid cere, the naked membrane of which is continued 

 over the cheeks and surrounds the eyes ; narrow ellip- 

 tical nostrils placed somewhat obliquely near the upper 

 edge of the beak : wings nearly equal to the tail in 

 length, of a rounded form, with the third and fourth 

 quill-feathers longest ; rather long, naked, and reticu- 

 lated legs ; and claws of moderate length and curvature, 

 but with little acuteness or power of grasping. From 

 this combination of structure it results that the birds 

 thus characterised, although very destructive in their 

 habits, are incapable of a lofty flight, of taking their 

 prey upon the wing, or of carrying it to a distant nest. 

 They are more frequently seen walking, and walk better, 

 than almost any other birds of prey ,• and have the 

 advantage of a much more varied and extensive bill of 

 fare than falls to the lot of the nobler species of their 

 tribe. It is to this latter circumstance that M. Vieillot 

 alludes in their generic appellation. 



In the Brazilian Caracara the whole upper surface of 

 the head is black, with the feathers slightly elongated 

 backwards, and capable of being partially elevated in 

 the shape of a pointed crest. The entire neck is of a 

 light brownish gray, which also forms the ground colour 

 on the breast and shoulders, but with the addition on 

 these parts of numerous transverse wavy bars of a 

 deeper broAvn. Nearly all the rest of the plumage is 

 of a tolerably uniform shade of blackish brown, with 

 the exception of the tail, which is at the base of a dirty 

 white, with numerous narro\^', "transverse, undulated 

 bands of a dusky hue, and in its terminal third black 

 without any appearance of banding. The beak is horn- 

 coloured at the tip and bluish at the base ; the iris 



