followed by such vast numbers of ducks, geese, shorebirds, 

 blackbirds, sparrows, warblers, and thrushes that observers 

 stationed at favorable points in the Mississippi Valley during the 

 height of migration can see a greater number of migrants than can 

 be noted anywhere else in the world. 



When many of these species, including ducks, geese, robins, and 

 yellow-rumped warblers, arrive at the Gulf coast, they spread out 

 east and west for their winter sojourn. Others, despite the perils of a 

 trip involving a flight of several hundred miles across the Gulf of 

 Mexico, fly straight for Central and South America. This part of the 

 route is a broad "boulevard" extending from northwestern Florida to 

 eastern Texas and southward across the Gulf of Mexico to Yucatan 

 and the Isthmus of Tehuantepec (Fig. 18, route 4). This route appears 

 to have preference over the safer but more circuitous land or island 

 routes by way of Texas or Florida. During the height of migration 

 some of the islands off the coast of Louisiana are wonderful 

 observation points for the student of birds, as the feathered travelers 

 literally swarm over them. 



Present detailed knowledge of the chief tributaries to the 

 Mackenzie-Great Lakes-Mississippi Valley route relates primarily 

 to waterfowl. Reference has been made already to the flight of black 

 ducks that reach the Mississippi Valley from southern Ontario. 

 Some individuals of this species banded at Lake Scugog, Ontario, 

 have been recaptured in succeeding seasons in Wisconsin and 

 Manitoba, but the majority was retaken at points south of the 

 junction of the Ohio River with the Mississippi indicating their main 

 route of travel from southern Ontario. 



A second route that joins the main artery on its eastern side is the 

 one used by eastern populations of lesser snow geese, including both 

 blue and white phases, that breed mainly on Southampton Island 

 and in the Fox Basin of Baffin Island. In the fall these geese work 

 southward along the shores of Hudson Bay and, upon reaching the 

 southern extremity of James Bay, take off on their flight to the great 

 coastal marshes of Louisiana and Texas west of the Mississippi River 

 delta. 



Great Plains Rocky Mountain Routes 



This route also has its origin in the Mackenzie River delta and 

 Alaska. The lesser sandhill cranes, white-fronted geese, and smaller 

 races of the Canada goose follow this route through the Great Plains 

 from breeding areas in Alaska and western Canada. It is used chiefly 

 by the pintails and American wigeons that fly southward through 

 eastern Alberta to western Montana. Some localities in this area, as 

 for example, the National Bison Range at Moiese, Montana, 

 normally furnish food in such abundance that these birds are induced 

 to pause in their migratory movement. Some flocks of pintails and 

 wigeons move from this area almost directly west across Idaho to the 

 valley of the Columbia River, then south to the interior valleys of 

 California. Others leave Montana by traveling southeastward across 



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