MIGRATION AMONG SHORE-BIRDS 179 



ity of Lake Athabasca in central Canada. In an air 

 line the species was thus spread across more than 

 six thousand miles of the earth's surface, while, by 

 the actual line of flight which these birds pursue, 

 the separation of northern and southern individuals 

 was infinitely greater. 



The flight of golden plover in spring begins casu- 

 ally at the end of January but is not fully under way 

 until March and April, when they pass north with 

 a rush to the northern coast of South America. 

 From here, instead of flying north over the sea on 

 a return journey by the course pursued in autumn, 

 they cross to the Gulf coast of the United States and 

 go north through the Mississippi Valley to their 

 Arctic breeding grounds. Their spring route is thus 

 over a course where the birds are entirely absent in 

 autumn. 



The Pacific form of this species, which nests along 

 the Bering Sea coast of Alaska and in northeastern 

 Siberia, travels south along the eastern coast of 

 Asia as far as Australia, Tasmania, and New Zea- 

 land, and through the Pacific islands from Hawaii 

 southward. The two groups of birds in this species 

 thus pursue wholly different courses in their flights. 



The turnstone is a species that is almost cosmo- 

 politan in range as it nests in the far north, to 70 

 degrees North Latitude and farther, and migrates 

 south throughout the World, though mainly along 



