BIRDS OF AEGENTINA, PARAGUAY, URUGUAY, AND CHILE 97 



two handsomely marked eggs. As I examined these and packed 

 them in my hat to remove them both caracaras hovered with harsh 

 grating calls a few feet above my head. The ground color of these 

 eggs varies from light-pinkish cinnamon to pinkish cinnamon, ob- 

 scured and in places almost obliterated by a heavy irregular wash 

 that varies from auburn and chestnut to hessian brown and liver 

 brown. About the large end these blotches become heavier and more 

 concentrated, and in places are almost black. These eggs measure 

 59.8 by 48 mm. and 54.5 by 48.5 mm. A caracara was gathering 

 sticks for a nest on November 15. 



A few were observed near San Vicente, Uruguay, from January 

 26 to February 2, 1921, and one was seen at Lazcano on February 

 7. North of Cordoba, Argentina, many were noted along the rail- 

 road on March 31 and at Tapia, Tucuman, the species was fairly 

 common from April 7 to 13. A few were recorded on the slopes 

 of the Sierra San Xavier, above Tafi Viejo, on April 17. 



On my return from Paraguay to the pampas of Buenos Aires I 

 noted that the carrancho of the south seemed larger than that ob- 

 served a fevr days previous in the northern Chaco, an impression 

 that has been sustained by a study of specimens. Skins from Chile 

 (one) and Argentina from the Straits of Magellan northward 

 (nine) show a wing measurement that varies from 410 to 442 mm. 

 (average 431 mm.). Skins from Brazil (Pernambuco, and one 

 from Bahia or Rio de Janeiro) and Puerto Pinasco, Paraguay 

 (three in all) range from 365 to 405 mm. (average 387 mm.). 

 (There seems to be no constant difference in size correlated with sex 

 in the caracaras.) The large form apparently ranges throughout 

 Argentina as I killed an adult female at Las Palmas, Chaco, on 

 July 20, 1920, with a wing measurement of 429 mm.) and into 

 Paraguay as a bird from that country without definite locality 

 (taken on the Page expedition in the fifties) has the wing 425 mm. 

 As the type locality of Miller's Falco plancus has been cited by 

 Shaw^^ as Tierra del Fuego, the southern form will stand as 

 Polyhorus plancus plancus. 



POLYBORUS PLANCUS BRASILIENSIS (Gmelin) 



Falco trasiliensis Gmelin, Syst. Nat., vol. 1, pt. 1, 17SS, p. 262. (Brazil.") 

 As has been stated aboA'e a male caracara secured at Kilometer 

 80, west of Puerto Pinasco, Paraguay, on September 15, 1920, has 

 a wing measurement of 405 mm., and so appears to belong to the 

 northern form, for which the name Falco hrasiliensis of Gmelin 

 is available. This is assumed to be the form that ranges from 



'sCim. Phys., 1796, p. 34. 



™ Type locality hereby fixed as Pernambuco. 



