96 BULLETIN laS, UNITED STATES NATIONAL MUSEUM 



constantly attracts attention when traveling through its range, 

 whether the birds are observed at rest in the top of some tree that 

 commands an outlook over open country, or in steady direct flight 

 toward some distant point. In the Chaco the caracara, as the bird 

 is called in Guarimi, is Imown as a scavenger that is tolerated so 

 that it is tame, and at times almost aggressive in its approach to 

 man. In the pampas these hawks are killed relentlessly because of 

 their depredations in eating out the eyes of newly-born lambs, and 

 in many districts the bird is becoming rare. 



At Las Palmas, Chaco, caracaras were common from July 13 to 

 August 1, 1920. When waste from a sugar factory killed many fish 

 in a small stream caracaras gathered in bands to feed on them, and, 

 it may be added, filched a number of mouse traps that I had sup- 

 posed were securely hidden in the brush along the bank. One was 

 observed eating a cavy, found lying dead, which like all large prey 

 was held firmly under one foot and torn into small bits with the 

 heavy bill. Near the Riacho Pilaga, Formosa, caracaras were re- 

 corded from August 7 to 19. One flew down frequently to disturb 

 feeding flocks of monk parrakeets {Myiopsitta in. cotorra) in a 

 sweet-potato field in hope that some cripple, wounded by the shoot- 

 ing of Indians, might fall into its clutches. It was not able to 

 seize the uninjured birds. On August 12 one flew to a large stick 

 nest, 9 meters from the ground in a quebracho tree standing in an 

 open savanna, to bring a bit of stick to add to the structure. After 

 this had been arranged satisfactorily the bird settled for an instant 

 in the nest cavity, and then flew to a limb overhead and surveyed 

 the nest carefully. At the town of Formosa, on August 23, cara- 

 caras flew back and forth above the strong current of the Paraguay 

 River in search for any carrion that might come downstream. 



In the vicinity of Lavalle, Buenos Aires, caracaras were observed 

 frequently from October 27 to November 15. The skull of a male 

 was secured on October 31. The birds were wary here as they were 

 shot relentlessly by the estanceros because of their destructiveness 

 to young stock. During the day carranchos ranged over the open 

 pampa but returned at nightfall to roost in trees in occasional 

 groves of ombu, tala, or eucalyptus. On November 6 I collected a 

 set of two fresh eggs near the coast about 25 kilometers south of 

 Cape San Antonio. The site was a small tree in a little grove 

 planted about a water hole, a spot remote from habitation and the 

 only suitable one available in a radius of several kilometers. The 

 nest, placed about 6 meters from the ground, was an untidy struc- 

 ture, bullry^ and heavy in appearance, made of dried stems of a 

 sharp-pointed rush, with broken ends stuck out in all directions. 

 The deeply cupped interior was lined in part with a felted mass 

 of pellets ejected by the parents, that formed a soft bed for the 



