Further Observations on Yomig Birds. 89 



particular animals, a matter of " experience and tradi- 

 tion." * There is probably no instinctive fear of man, 

 and if one move gently and quietly, one may feed young 

 fledgelings in the nest. There is probably no instinctive 

 fear of a cat, and if she creep up stealthily she may 

 get close to young birds, unless they hear the alarm 

 note of their parents or other birds. What does seem 

 to evoke an instinctive response is the rapid approach 

 of any quickly moving vigorous animal, or even a leaf 

 driven by the breeze. "A piece of newspaper," says 

 Mr. Hudson, "carried accidentally by the wind is as 

 great an object of terror to an inexperienced young bird 

 as a buzzard sweeping down with death in its talons." 

 As experience is gained, it is the unusual which evokes 

 the response which indicates fear. A plover will drop and 

 crouch on hearing the crisp crunch of a paper bag crushed 

 in the hand. 



With birds reared under natural conditions by the 

 parents, their alarm note serves as a warning, and, as 

 Mr. Hudson well describes, tradition hands on the fear 

 of particular enemies and dangerous animals. " Hawks," 

 he says, " are the most open, violent, and persistent 

 enemies birds have ; and it is really wonderful to see 

 how well the persecuted kinds appear to know the power 

 for mischief possessed by different raptorial species, and 

 how exactly the amount of alarm exhibited is in pro- 

 portion to the extent of the danger to be apprehended." 

 These differences, however, would seem to be neither the 

 result of heredity nor of merely individual acquisition, 

 but of racial experience handed on by tradition through 

 the instrumentality of danger notes. 



Here too, however, as in the case of response to the 

 sight of materials which may serve for food, or which are, 



* " Naturalist in La Plata," chap v. p. 53. 



