RHEIDAE 



31 



feathers of the wings and back. Hens are not so dark, and Mr. 

 Hudson says ^ that in JR. darivini the young are dusky grey 

 and are hatched with the 

 legs feathered to the toes. 

 Ilheas are shorter than 

 Ostriches by about a couple 

 of feet, a. americana being 

 the largest form; the feathers 

 are much rounded, broad, 

 and Aery soft. Fossil re- 

 mains occur in the Upper 

 Tertiary or quite recent 

 deposits of South America. 

 The members of this 

 family find their favourite 

 haunts on the treeless flats 

 of the Argentine Pampas, 

 the scrub-covered plains of 

 Patagonia, or the dry open 

 Sertoes of Brazil, where 

 their acute vision enables 

 them to detect the approach 

 of enemies from afar. 

 Small flocks of from three 

 to seven individuals are met 

 with at certain seasons, and 



Fig. 9. — Nandu. 



Shea americana. 



X J,T. 



parties of twenty or thirty 



at other times — often with deer or guanacos — so it would appear 

 that, as in the case of the Ostrich, larger companies are formed 

 after the young are able to provide for themselves. The birds 

 become exceedingly tame when not molested, but when danger 

 threatens they run at great speed, doubling upon their pursuers 

 constantly, or crouching down among bushes or other cover, if they 

 think they can escape observation. In the latter case they will 

 lie closely until almost trodden upon, and may be shot before they 

 rise by the hunter who cautiously approaches their hiding-place, 

 as the head is usually visible above the surrounding vegetation. 

 "When moving at full pace the wings have normally a somewhat 

 drooping position, but they are raised alternately above the back 



^ Argentine Ornithology, ii. 1889, p. 220: 



