2 3 



Wild Birds 



submit to the taming process, and a few become tame in the nat- 

 ural state. Whatever principles of evolution shall eventually 

 prove to be true, we may safely regard the higher vertebrates 

 which are now tame in their natural state as the descendants of 

 wild ancestors. 



As a rule, no wild mammal or bird approaches man without 

 some inducement. Unless some other instinct be aroused, it 

 comes, if at all, to defend or feed its offspring, to appease its 



Fig. 139. Red-eyed Vireo cautiously approaching her nest. Compare 

 such attitudes with Figs. 60-63, which express no fear. 



hunger, or in very rare cases to find protection from danger. 

 The taming process depends, as we have just seen, upon the 

 ability to form new associations, and may be brought about 

 artificially by restraint as when a wild animal is caged and new 

 habits are, as it were, forced upon it, or by means of strong lures. 

 Of the latter, one of the best is food in the presence of hunger, 

 but the strongest of all are the young at a certain stage of 

 growth. In order to tame a wild animal without recourse to 

 restraint there must be some means of breaking the ice, or begin- 

 ning a course of instruction, by chaining it to a fixed point. In 

 case of birds with young the invisible chain is parental instinct, 

 which inhibits fear and holds the animal to a given spot. We 



