82 HOW TO STUDY BIRDS 



might call them, corresponding to the " lanes of nav- 

 igation " used by trans-Atlantic steamships. River- 

 valleys are notable highways of migration, as is the 

 coast-line. Certain species are peculiarly limited in 

 their distribution and migrate only along rather well- 

 defined pathways, especially along the valleys of riv- 

 ers or the sides of mountain ranges. 



In some cases the course of migratory birds is lo- 

 cally deflected by conditions of topography. In il- 

 lustration of this last it has been shown by Dr. L. B. 

 Bishop, as a result of a long series of observations, 

 that land-birds in migration following the Connecticut 

 shore-line, when they come within sight of New Ha- 

 ven Harbor, are deflected and fly miles inland around 

 this bay, rather than venture a mile or two across it. 



For many people the period of the spring migra- 

 tion is filled with exacting demands upon their time. 

 We begrudge the hours of joy and sunshine in which 

 we find ourselves cooped up indoors. I can still see 

 myself writing examinations when the birds were 

 warbling outside, literally gnashing my teeth in im- 

 potent vexation. Well, perhaps we appreciate the 

 spring birds even thus more than though we could 

 always be among them. Perhaps if we systematize 

 the time, we can add to our opportunities. It may 

 be a case of " early to bed and early to rise." 



Much can be done even in a few odd moments 

 from time to time. The birds in the spring migra- 

 tion are more in evidence than at any other period. 

 They are on the move and in sight, they sing loudly 



