98 BULLETIN 133, UNITED STATES NATIONAL MUSEUM 



northern Paraguay northward through Brazil. The status of the 

 bird from the coastal region of extreme southern Brazil (Santa 

 Catherina and Rio Grande do Sul) is uncertain. From September 

 6 to 30, 1920, I found caracaras common in the country about 

 Puerto Pinasco. As they were not persecuted in this region they 

 came in numbers about ranch buildings in search of offal from the 

 killing pens. Their habits do not differ from those of the southern 

 form. 



HERPETOTHERES CACHINNANS QUERIBUNDUS Bangs and Penard 



Herpetotheres cachinnans queribundus Bangs and Penard, Bull. Mus. 

 Conip. Zoul., vol. 63, June, 1919, p. 23. (Pernambueo, Brazil.) 



The southern laughing falcon was seen first on July' 21, 1920, near 

 Las Palmas, Chaco, when an adult female was taken as it rested on 

 a dead stub in an opening in the forest. Farther northward at the 

 Riacho Pilaga, in central Formosa, from August 8 to 20 the species 

 was more common, and two additional females were shot on August 

 14 and 20 (the latter preserved as a skeleton). At Kilometer 80, 

 west of Puerto Pinasco, Paraguay, one was seen September 12, and 

 at Kilometer 200 two were found on September 25. The birds, 

 usually in pairs, inhabit the taller growths of heavy forest where 

 they rest on open perches surrounded b}'^ dense heavy growth. 

 Where not molested they come out into more open regions. 

 Though of heavy build, seeming strong and powerful, they ar2 

 sluggish in ordinary habit and are seldom seen save at rest. On 

 only one occasion did I observe one turning in circles in the air 

 above the trees. 



One is not long in the haunts of the laughing falcon without be- 

 coming familiar with its strange loud notes, though it may be some 

 time before the bird is seen. The call begins as a single note, given 

 at short intervals, and then changes to a more rapid repetition of 

 varied sounds. After two or three minutes the mate of the per- 

 former may join in and the birds call rapidly, first in alternate short 

 notes and then in a strange medley, a weird, unearthly concert, start- 

 ling indeed to one not familiar with its source, that may be con- 

 tinued without cessation for 10 minutes. These strange duets were 

 especially impressive when heard at dusk. Countrymen related 

 that the birds were very observant and announced by their calls the 

 passage of men through the forest. 



The falcons themselves are handsome birds, their heavy white 

 crests and boldly marked black head being no less impressive than 

 their notes. The Toba Indians knew them as gua kow in evident 

 imitation of their calls, while in Guarani they were called Guaycuru, 

 a word signifying a Chaco Indian, usually designating a warlike 

 type. 



