16 



BULLETIN 185, U. S. DEPARTMENT OP AGRICLTLTUEE. 



land bird. But it is a favorite fall route for thousands of water 

 birds, notable among which is the golden plover. 



T Fig. 6. — Migration of the cliff swallow {Petroclielidon lunifrons). This is a day migrant, feeding on the 

 wing; hence it keeps near land and journeys around the Gulf of Mexico, instead of flying across it as is 

 done by the black-poll warbler (fig. 5) which migrates at night. (See pp. 19 and 26.) 



The journey of this plover is wonderful enough to be given in 

 detail. Its most striking characteristics are a single flight of 2,400 

 miles — the longest known flight of any bird — and an eUiptical migra- 

 tion route following different paths for the spring and the fall 



