94 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



rump and two light patches on either wing. Small birds show no 

 fear of them, and feed or rest with unconcern though chimangos 

 may be near at hand, except when they have nests containing eggs 

 or young, when these little hawks are harried mercilessly by every- 

 thing from small passerines to the spur-winged lapwings, doubtless 

 for good cause, as the chimango delights in helpless prey. On one 

 occasion I observed one pecking steadily in an attempt to drag out 

 the entrails of a lamb, too helpless from some disease to move other 

 than to flinch at the cruel strokes of the bird's beak. At other times 

 the chimango may be of considerable economic value, as in Uruguay, 

 during a period of invasion by locusts, chimangos were seen in bands 

 that at times numbered 30 or 40 individuals gathered to feed on this 

 food. The hawks walked or ran about on the ground or swooped 

 down at their prey from above, and fed until completely satiated. 

 At Carrasco, Uruguay, on January 16, I obserA^ed 16 gathered over 

 an area of sand dunes to feed on a small cicada {Proama, species) 

 abundant at the time. Their feet are too weak to afford firm grasp 

 with the talons, but on the ground they walk with ease and freedom. 

 One that I wounded slightly ran so swiftly that it was captured only 

 after a long chase. The birds are usually more common in the 

 vicinity of water than elsewhere, and drink copiously and frequently 

 even though the water may be quite brackish in taste. 



MILVAGO CHIMACmMA CHIMACHIMA (Vieillot) 



Polyhorus chimachima Vieillot, Nouv. Diet. Hist. Nat., vol. 5, 1816, p. 259. 

 (Paraguay.) ""5 



In addition to the color characters assigned by Bangs and Penard ^'^ 

 to Milvago cMmachima cordata from Panama, this northern form 

 seems to be slightly smaller, as in the type, a female, the wing is 

 given as 292 mm., and the tail 196 mm., and in a male topotype the 

 wing is 275 mm., and tail 183 mm. In two adult females of the 

 southern form from Las Palmas, Chaco, and Riacho Pilaga, For- 

 mosa, the measurements are as follows: Wing, 305, 302 mm.; tail, 

 197, 197 mm. An adult male from Kilometer 80, Puerto Pinasco, Para- 

 guay, measures, wing 292 and tail 187 mm. There is considerable 

 variation in color of the head and underparts in adults of the typical 

 form, some being much paler than others. 1 believe that the 

 plumage, as it ages after the molt, is subject to considerable 

 bleaching. 



This small carrion hawk, known as the chimango, or, more prop- 

 erly in Guarani, as kiriri^ was encovmtered first at Las Palmas, 

 Chaco. On July 27, 1920, one or two were found in the tops of low 



■""No locality is designated in Vieillot's original description but the type locality has 

 been assumed to be I'aiaguay as tlie description is taken from Azara. 

 "Bull. Mus. Comp. Zool., vol. 62, April, 1918, p. 35. 



