Cape San Antonio, Buenos Ayres. 409 



arrow-head conclusively proves that these belonged to the 

 ancient Guarani Indians^ and not to the present races now 

 inhabiting the pampas of Buenos Ayres. 



What follows, then, as may be gathered from these notes, 

 is a natural division of all our birds into three great classes — 

 namely, those of the wood, the plain, and the swamp. The 

 rincones have also a few species peculiar to them ; but, again, 

 to counterbalance that, the shore has none. 



The total number of species found here is at least one 

 hundred and twenty ; and I hope and expect it may reach ten 

 or fifteen more. As already remarked, the following con- 

 stitute only a small portion of that number; and it remains 

 for future observations to work up the balance of the orni- 

 thology in the neighbourhood of Cape San Antonio. 



1. Geranoaetus melanoleucus (Vieill.). 



The '' Aquila " of our natives (Spaniards) . 



Rather rare here, and very local in its habits. A pair used 

 to frequent one of the woods surrounding our head station, 

 and bred there for many years ; but they abandoned their 

 eyrie before my time (1872), though I have since that date 

 seen two adults and two young birds (in the brown plumage) 

 at various intervals. In the plains I have twice seen single 

 specimens, in both cases at carrion, the Caranchos {Polyborus 

 tharus) keeping at a respectful distance during the repast. 

 Where I can always make sure of finding them is at the 

 entrance to our rincones, two or three pairs breeding there 

 in a narrow belt of woods, the eyries being generally a couple 

 of miles apart. 



Its flight is slow ; and when disturbed it generally ascends 

 in spiral circles. When doing so it does not look very 

 majestic, the wings being too broad in proportion to their 

 length. Its whereabouts may often be detected by an atten- 

 dant flock of Caranchos, particularly in the case of a young 

 bird. As soon as it rises from the ground or from a tree, 

 these begin to persecute it, ascending spirally also, and making 

 dashes at it, while the Eagle only turns its head watchfully 

 from side to side, the mere action being sufficient to avert the 

 threatened coUisioo. 



