WILD LIFE OF ORCHARD AND FIELD 



females and young. I am careful to make this 

 matter of the succession of ages clear, because of 

 its notable significance in the problem: How do 

 birds find their way? The old answer was short 

 and easy: Instinct tells them. This means, if 

 it means anything, that a bird is born with an 

 intuitive knowledge of a road he has never seen, 

 perhaps crossing the ocean. In some instances 

 it would mean an intuitive knowledge of two roads, 

 for one of the curiosities of American migrations, 

 at least, is the fact that certain species follow one 

 route in the spring and another quite different 

 one on their return in the autumn. Moreover, 

 migration routes are rarely straight lines north 

 and south, to which the little creatures might be 

 kept by some mysterious "sense of polar direction," 

 but are usually somewhat roundabout, often crook- 

 ed, and sometimes squarely east and west for a 

 large part of the course. Then we encounter such 

 curiosities as the behavior of that warbler common 

 in summer in Alaska, which never migrates along 

 the American coast with the other birds, but crosses 

 to Siberia and comes and goes to the tropics by 

 the far longer Asiatic road. Another curiosity, 

 which may be mentioned here as well as anywhere, 

 is this : Where birds have been led, by the influence 



io8 



