THE VIREO AND THE COWBIRD 135 



for the two or three weeks after leavmg the nest 

 he rehed entirely on his parents for his food. They 

 taught him what insects to eat and when and how 

 to find them, how to look on the underside of a 

 leaf for the small green caterpillars, how to dart 

 quickly at any insect which had wings, and so 

 many other things about which we know absolutely 

 nothing. For there is much that a bird must know 

 if he would win his way through hfe. Let him be 

 slow to learn and his life will be a short one. For 

 nature's law is, and always will be, " the survival ot 

 the fittest." 



