44 



ROUTES OF MIGRATION 



Porto Rico from the westward. This route, however, is followed by 

 only a small portion of the birds which migrate southward, through 

 Florida and the Bahamas, into the Greater Antilles. If they continue 

 their journey to South America, most of them do so. through Jamaica, 

 the 400 miles of water separating this island from northern South 



FIG. 7. Migration of the Bobolink. A species which breeds west of the Rocky 

 Mountains, but migrates through the southeastern United States, reaching South 

 America through the Greater Antilles and Central America. 



Dotted area Breeding range. Black area Winter range. Arrows Migration 

 route. 



America being evidently no barrier to such great travelers as the Bobo- 

 link and Blackpoll Warbler. 



Within the limits of the United States, coast-lines, mountain 

 chains, and the larger river valleys, appear to be followed by birds 

 in their migrations; nevertheless, there is a more or less pronounced 



