420 Mr. E. Gibson on the Ornithology of 



thistles, and the other two respectively on a tuft of grass 

 and among some "jume" {Salicornia) in the rincones. 

 There were several trees near the two latter ; so their pre- 

 ference for the ground requires some other explanation. Both 

 were very slight structures. 



The swamp-built nests are usually placed among the duras- 

 nillos and rushes, are annually augmented and repaired, and 

 similar in construction and materials to those first described. 



The eggs never exceed three ; but I have frequently taken 

 that number of fully fledged young ones in a nest ; and re- 

 pulsive-looking savages they are. The average measurement 

 of thirty-one specimens gives 2^^ x 1|^, the variation being 

 from 2f § X 2^Q (an exceptionally broad specimen) to 2^^ x 

 If^. In colour they may be likened to the Peregrine or 

 Icelandic Falcon's, the typical eg^ being dull reddish in the 

 ground, with darker markings of the same. Two notable 

 exceptions in my collection have a dirty white ground, with 

 dark brown blotches at one extremity, the remainder of the 

 egg being only spotted with that colour. From its size and 

 fine colour, the egg of Polyborus tharus at once attracts the 

 eye on examining a cabinet of Buenos-Ayrean eggs. 



9. MiLVAGO CHiMANGo (Vicill.). Chimaugo. 



Equally common with the last species, and of much the 

 same habits. Querulous, restless, quarrelsome, and prying, 

 it makes its presence incessantly felt. 



Carrion, with small snakes, frogs, insects, &c., form its 

 food j and 1 have often seen it perched on the fresh sheep- 

 skins, tearing off any small scraps of meat, but never injuring 

 the hide. As one writer has aptly said, " the Chimango is 

 the last to leave any carcass, and may be seen running up 

 and down inside the skeleton ribs, long after Carancho and 

 Vulture have given them up as picked bare.'' Much bolder 

 than the Carancho, it will hover closely overhead while an 

 animal is being flayed, or alight on the ground within a yard 

 of the operator. 



Two Chimangos cannot remain within a few yards of each 

 other in a peaceable manner. They must always be resenting 



