50 BIRDS OF LA PLATA 



infrequently on a tree* Mr, Gibson describes one, 

 which he found on the top of a thorn-tree, as a 

 structure of large sticks, three feet in diameter, the 

 hollow cushioned with dry grass* It contained two 

 eggs, dull white, marked with pale reddish blotches* 



Mr* Gibson compared its cry to a " wild human 

 laugh," and also writes : " Its whereabouts may often 

 be detected by an attendant flock of Caranchos 

 (Polyborus tharus), 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 

 collision*" 



Gay, in his Natural History of Chili, describes the 

 affectionate and amusing habits of an Eagle of this 

 species which he had tamed. It took great delight in 

 playing with his hand, and would seize and pretend 

 to bite one of his fingers, but really with as much 

 tenderness as a playful dog displays when pretending 

 to bite its master* It used also to amuse itself by 

 picking up a pebble in its beak, and with a jerk of 

 its head toss it up in the air, then seize it in its 

 claws when it fell, after which it would repeat the 

 performance* 



