LINES OF MIGRATORY FLIGHT 139 



mentioned, so far as known, return north in spring 

 by routes that carry them along or over the land, so 

 that the outer sea lane is used apparently by few 

 individuals in returning to the north. 



From the interior basin that drains into Hudson 

 Bay and the Arctic Ocean many birds converge in 

 southward flight on the Great Lakes, and then pass 

 directly south, as is the case with the blue goose, 

 which travels from its breeding grounds somewhere 

 in western Keewatin to this point and then drives 

 south to the Gulf coast of Louisiana and Texas. 

 Others from this same point, including many ducks 

 and geese, pass directly southeast toward the head of 

 Delaware and Chesapeake bays and ultimately 

 reach Currituck Sound and the coast of South Caro- 

 lina. There is also migration, not indicated on the 

 map since it is only partly understood, among a few 

 birds from the interior plains region to the southeast 

 that brings such species as LeConte's sparrow to the 

 coast of South Carolina. 



Migrants that continue to wintering grounds 

 beyond Florida and the Gulf Coast have now a 

 choice of three travel lanes. One of these leads 

 through Florida, Cuba, the Bahamas, Santo Do- 

 mingo, Porto Rico, and the Lesser Antilles, to South 

 America. Though a considerable number of migrant 

 land birds embark on this passage the majority are 

 content to linger in Antillean islands, and few seem 



