MIGRATIONS OF WATERFOWL 



and juveniles or who cherish the oldest and fondest of all migration mys- 

 teries, the idea of an inborn awareness of the direction and the route to 

 the wintering grounds. 



In any analysis of migrational orientation, I am sure we must distin- 

 guish between experienced adults and inexperienced juveniles just learn- 

 ing their place in the world. The primary dispersals of ducks from the natal 

 ranges carry youngsters toward rendezvous areas where they gather to- 

 gether, not only with many of their own age, but with adults as well. As 

 already discussed in Chapters 8 and 10, vast numbers of juvenile ducks 

 make part or all of their final autumn journey to the wintering grounds 

 with experienced adults in the traditional mass migrations. Juveniles that 

 accompany their elders, whether they are children, as in geese and swans, 

 or merely companions, as in ducks, may learn the flyways and standard 

 directions, which thus become traditional.* But however many young reach 

 the wintering grounds in this way, some juvenile waterfowl (and in some 

 species of birds, perhaps all young-of-the-year) gain the wintering places 

 without the companionship of experienced adults. 



An analysis of juvenile travel in autumn must first distinguish between 

 an ecological and geographical goal. Because the immature bird arrives at 

 an ecologically suitable situation on its winter range, the literature often 

 assumes an innate awareness of that place. When a young duck finds a sago 

 bed on the far side of its natal pond, nobody claims there is an inborn 

 guidance to that special location, nor to the stubble fields ten miles south 

 of the home marsh, nor even to another marsh in the home province. When 

 the juvenile eventually arrives in Minnesota or North Dakota, we credit 

 it with no innate tie to these places. But somehow, when a young bird 

 finally attains a wintering area a thousand miles or more from its birthplace, 

 this feat is often explained by assuming an innate bond to that geo- 

 graphic location.f 



* In ducks I found the existence of mass migrations poorly documented in the literature, 

 and I believe this holds for many other species. While it may be true that in some kinds all 

 young-of-the-year arrive on the wintering grounds independently of adults, I believe that mass 

 autumn migrations are greatly underrated as the vehicle for the autumn travels of inexperi- 

 enced juveniles. Simmons ( 1951:406), discussing raptor migration, says, "I feel the significance 

 of socially-facilitated behavior has been under-estimated. There is a definite tendency for the 

 birds to follow the movements of their companions, thus effecting general movement in the same 

 direction." To show that large numbers of young in many species regularly travel part or all of 

 the way to the wintering grounds en masse with adult companions is not to explain all juvenile 

 travel. But this type of movement must account for the winterward passage of great numbers of 

 young birds in many species. 



t In some European species, like the Stork, European Sparrow Hawk, Starling, and Hooded 

 Crow (Mayr, 1952), and in the American Crow (Rowan, 1946), certain experiments have been 



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