AVES FALCONID/K. 



621 



Geographical Range. Tropical South America ; south to the Rio Negro 

 region of Patagonia; north into Central America and southern Mexico; 

 intergrading thence with the form sennetH, which represents the typical 

 albiciimltitus throughout Mexico, southern Texas and southern Arizona. 



Mr. Hatcher and his associates did not penetrate to that part of Pata- 

 gonia where these birds have been found and the descriptions in the fore- 

 going pages are from the series of birds in the British Museum of Nat- 

 ural History and in the American Museum in New York. 



Fio. 311. 



Tackytriorclus albicaudatus.. Immature male. From bird in the American Museum. 



One-fourth natural size. 



The birds, as found in their northern range, nest in low bushes and trees, 

 often in the yucca and sometimes in cacti. But little seems to have been 

 contributed to the life history of this hawk. It is a bird that feeds on 

 smaller mammals and at times on carrion, but rarely on other birds. 

 The eggs are not in the collections of the British Museum and are believed 

 to be undescribed. 



