MIGRATIONS OF WATERFOWL 



hard weather, like those of Canvasbacks from the Susquehanna to Curri- 

 cuck, or north in unseasonably mild weather, like the massive travel of North 

 Dakota Mallards back into Manitoba. Or they may be cross-country, from 

 one flyway to another, like the "round-robin" type of movement of Pintails 

 (Low, 1949). 



Bandings show that adults as well as juveniles wander about the winter 

 ranges in this way; and of Mallards making November arrivals at Delta 

 from North Dakota, I found both adults and juveniles in hunters' bags. Such 

 vagrancies, however, do not concern the whole of the wintering population, 

 some individuals and some large aggregations staying in one place through- 

 out the winter. 



The winter vagrancy ends with the rise of the sexual cycle, when travel is 

 directed toward the breeding range upon the start of homeward migration. 



Homeward spring migration is the relentless drive to the nesting place. 

 It may consume several or many weeks; there may be interruptions and 

 lags, usually due to the weather; but it is a persistent and unalterable move- 

 ment toward the geographic place of home. 



On the other hand, in travel from the breeding range to the wintering 

 grounds, some or many ducks undoubtedly follow vagrant movements be- 

 fore or between the mass fall migrations. Vast segments of the population 

 move directly and swiftly over long distances in mass fall migration, and 

 probably all adult birds and most young waterfowl participate in at least 

 one mass passage during the course of the autumn. But the random travel 

 of the young birds (with an ecological and meteorological bias toward the 

 south in autumn) and the vagrancies of adults are variables of autumn that 

 are not found in spring. 



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