I50 THE MIGRATIONS OF BIRDS 



these shore-birds pass south with the coming of 

 autumn in the northern hemisphere, cross the Equa- 

 tor, and then follow the advance of the southern 

 spring to their winter home, where they live amid 

 summer weather. At the close of the southern sum- 

 mer, with the coming of colder weather in February 

 and March, they withdraw northward and again 

 cross the Equator, to follow the northern spring in 

 its advance to their breeding grounds in the northern 

 United States, Canada, and Arctic America. Their 

 journey thus is timed to take advantage of the shift- 

 ing seasons of both hemispheres. 



In their movements through South America these 

 northern species have three main routes, one along 

 the Atlantic Coast, one that skirts the Pacific Coast 

 line, and a third that follows north and south along 

 the great interior river system of the Paraguay and 

 Parana. There is also migration, not well under- 

 stood, across the high plateaus of the Andes, parti- 

 cularly in the vicinity of Lake Titicaca. 



With regard to the movements of native birds in 

 South America, there are many observations on 

 record in the writings of Dabbene, Gibson, Hudson, 

 and others, while J. L. Peters has given an account 

 of the spring arrival of a number of species in north- 

 ern Patagonia. 



Migratory movements are as readily evident to 

 the field observer as in northern regions. Flocks of 



