MIGRATION ROUTES AND F i Y w A Y s 47 



MIGRATION ROUTES AND FLYWAYS 



CONTRIBUTED BY 

 FREDERICK C. LINCOLN 



In Charge, Distribution and Migration of Birds, 



Division of Wildlife Research, Fish and Wildlife Sen>ice, 



U. S. Department of the Interior 



The terms "migration route" an "flyway" have in the past been 

 used more or less indiscriminately, but tor the purpose of this article 

 and in order that the full picture of migration may be better portrayed, 

 it seems desirable to designate as migration routes the individual lanes 

 ol avian travel from breeding grounds to winter quarters, and as flyways 

 those broader areas into which certain migration routes blend or come 

 together in a definite geographic region. The individual migration routes 

 may be likened to long trails, while the flyways resemble arterial boule- 

 vards to which the routes are tributary. Except along the coasts, the 

 boundaries of these flyways cannot always be sharply defined, particu- 

 larly in the northern part of the interior, for the reason that broadly 

 speaking all the country from Nebraska north to the Arctic coast is 

 one great breeding ground that is used by many species of migratory 

 waterfowl. From about latitude 45 southward to the Gulf coast, how- 

 ever, these flyways are fairly well marked, and it is within this region 

 that most of the sport shooting takes place. The status of the ducks and 

 geese in the different flyways, therefore, is of great interest not only to 

 naturalists but also to sportsmen. 



It is now a matter of common knowlege that migratory birds follow 

 certain definite routes on their journeys to and from breeding and win- 

 ter quarters, but it is not generally understood that these routes are fol- 

 lowed by the same groups of individual birds during successive years. 

 Migration studies by the banding method have shown that by adhering 

 more or less rigidly to any particular flyway the ducks and geese tend 

 to perpetuate not only that ancestral route but also the groups of in- 

 dividuals that use it. 



THE FOUR IMPORTANT FLYWAYS 



The four major waterfowl flyways of North America and their 

 tributary migration routes are sketched in the following paragraphs. 



THE ATLANTIC FLYWAY 



The Atlantic flyway (fig. 32) may be described as extending from 

 the Atlantic coast w r est to the Allegheny Mountains and curving north- 

 westward across northern West Virginia and northeastern Ohio to the 

 western end of Lake Erie. It has at least three primary migration routes 

 and as many more that are also important as tributaries. 



