ARGENTINE COW-BIRD 83 



the language of their real parents, rising to receive 

 food when summoned, and concealing themselves 

 or trying to escape when the warning note is given. 

 How does the young Molothrus learn to distinguish, 

 even by sight, its foster-parent from any other bird 

 approaching the nest t It generally manifests no fear 

 even at a large object. On thrusting my fingers into 

 any nest I find the young birds, if still blind or but 

 recently hatched, will hold up and open their mouths 

 expecting food ; but in a very few days they learn 

 to distinguish between their parents and other objects 

 approaching them, and to show alarm even when 

 not warned of danger. Consider the different be- 

 haviour of three species that seldom or never warn 

 their offspring of danger. The young of Synallaxis 

 spixi, though in a deep domed nest, will throw itself 

 to the ground, attempting thus to make its escape. 

 The young of Mimns patagonicus sits close and 

 motionless, with closed eyes, mimicking death. The 

 young of our common Zenaida, even before it is 

 fledged, will swell itself up and strike angrily at the 

 intruder with beak and wings ; and by making so 

 brave a show of its inefficient weapons it probably 

 often saves itself from destruction. But anything 

 approaching the young Molothrus is welcomed with 

 fluttering wings and clamorous cries, as if all creatures 

 were expected to minister to its necessities. 



I found a young Molothrus in the nest of a 

 Screaming Finch, Spermophila c&rulescens ; he cried 

 for food on seeing my hand approach the nest ; I 

 took him out and dropped him down, when, finding 



