86 The Naturalist in La Plata. 



was in sight, and, squatting at my feet, endeavour 

 to conceal themselves by thrusting their heads and 

 long necks up my trousers. If I had caused a 

 person to dress in white or yellow clothes for several 

 consecutive days, and had then uttered the warning 

 cry each time he showed himself to the birds, I 

 have no doubt that they would soon have acquired a 

 habit of running in terror from him, even without 

 the warning cry, and that the fear of a person in 

 white or yellow would have continued all their lives. 

 Up to within about twenty years ago, rheas were 

 seldom or never shot in La Plata and Patagonia, 

 but were always hunted on horseback and caught 

 with the bolas. The sight of a mounted man would 

 set them off at once, while a person on foot could 

 walk quite openly to within easy shooting distance 

 of them ; yet their fear of a horseman dates only 

 two hundred years back — a very short time, when 

 we consider that, before the Indian borrowed the 

 horse from the invader, he must have systematically 

 pursued the rhea on foot for centuries. The rhea 

 changed its habits when the hunter changed his, 

 and now, if an estanciero puts down ostrich hunting 

 on his estate, in a very few years the birds, although 

 wild birds still, become as fearless and familiar 

 as domestic animals. I have known old and ill- 

 tempered males to become a perfect nuisance on 

 some estancias, running after and attacking every 

 person, whether on foot or on horseback, that 

 ventured near them. An old instinct of a whole 

 race could not be thus readily lost here and there 

 on isolated estates wherever a proprietor chose to 

 protect his birds for half a dozen years. 



