regionalizing the harvest of waterfowl for areas of different 

 vulnerability of hunting pressure. 



Bellrose (1968) identified corridors of southward migrating 

 waterfowl east of the Rocky Mountains and determined, through 

 statistical analyses, the relative abundance of birds in each. He 

 showed major corridors of dabbling duck movements down the Great 

 Plains and Missouri-Mississippi river valleys with minor off shoots at 

 various points from these corridors eastward to the Atlantic coast 

 where they joined equally minor eastern movements from the North 

 (Fig. 13). Bellrose's map of migration corridors for the diving ducks 



Dabbling Ducks East of Rockies 



1,500,000-3,000,000 



750,000-1,500,000 



I 



350,000-750,000 

 100,000-350,000 

 30,000-100,000 

 1,000-30,000 



Figure 13. Migration corridors used by dabbling ducks east of the Rocky Mountains 

 during their fall migration (After Bellrose 1968). 



63 



