migration being entirely coastwise. Still another cross-country route 

 between the Mississippi Valley and the Atlantic coast remains to be 

 briefly described. It is not yet well understood, but the banding of 

 ducks such as the blue-winged teal on the coastal saw-grass marshes of 

 South Carolina has revealed that there is a migration route across the 

 Appalachians to the Mississippi Valley. Birds marked in these 

 marshes have been retaken in Tennessee and Kentucky, as well as in 

 other States farther north in the Mississippi Flyway. 



Mackenzie Valley-Great Lakes-Mississippi Valley route 

 and tributaries 



Easily the longest route of any in the Western Hemisphere is that 

 extending from the Mackenzie Valley past the Great Lakes and down 

 the Mississippi River, including its tributaries. Its northern terminus 

 is on the Arctic coast in the regions of Kotzebue Sound, Alaska, and 

 the mouth of the Mackenzie River, while its southern end lies in Pata- 

 gonia. During the spring migration some of the shore birds traverse 

 the full extent of this great path, and it seems likely that the night- 

 hawk, the barn swallow, the blackpoUed warbler, and individuals of 

 several other species that breed north to Yukon and Alaska must twice 

 each year cover the larger part of it. 



For more than 3,000 miles — from the mouth of the Mackenzie to the 

 delta of the Mississippi — this route is uninterrupted by mountains. 

 In fact, there is not even a ridge of hills high enough to interfere with 

 the movements of the feathered travelers, and the greatest elevation 

 above sea level is less than 2,000 feet. Well timbered and watered, the 

 entire region affords ideal conditions for the support of its great hosts 

 of migrating birds. It is followed by such vast numbers of ducks, geese, 

 shore birds, blackbirds, sparrows, warblers, and thrushes, that observers 

 stationed at favorable points in the Mississippi Valley daring the height 

 of migration can see a greater number of species and individuals than 

 can be noted anywhere else in the world. 



Starting in the region of Kotzebue Sound, Alaska, the route extends 

 eastward across northern Alaska and joins another that has its origin 

 at the mouth of the Mackenzie River. The line of flight then trends 

 a little east of south through the great lake system of central Canada, 

 where it is joined by two or three other routes from the northeast that 

 have their origin on the central Arctic coast. Continuing southward 

 the migrating flocks are constantly augmented by additions to their 



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