TRADITIONS OF WATERFOWL 



sions there may be a previous history of waterfowl breeding in past years, 

 but often the period of drought is longer than the life-expectancy of ducks ; 

 hence the regions are entirely new to the modern generation that moves 

 in during a wet cycle. 



New areas often remain wet for only a few years ; then water and ducks 

 are gone again. On the Portage Plains most of the sloughs of 1945 held 

 water and nesting ducks each year until 1950, a span of six consecutive 

 breeding seasons. By 1951 some had become dry and duckless; by 1952 

 most were dry. With ducks there is an ebb and flow of breeding populations 

 at the edge of permanent ranges. Many large marshes, such as the Delta, 

 never lose all their water or their ducks. The sloughs and potholes of the 

 true prairie are relatively stable. But in the western mixed prairie, water and 

 ducks, like agricultural crops, fluctuate severely. 



The degree of pioneering in ducks, it seems to me, depends on the 

 proximity of new areas to established nesting grounds. In the Dakotas and 

 the prairie provinces of Canada there is a large and established breeding 

 population in the marshes and smaller water areas of the true prairie. In 

 years when the water comes to the shallow depressions of the western 

 plains region, the shiftings of breeders originates from the dense popula- 

 tion centers not far away. Farther south and east on less densely populated 

 breeding grounds, there are fewer waterfowl centers of abundance from 

 which birds may overflow. In the Delta region I have noticed that ducks 

 pioneer more quickly and more abundantly to new ponds within ten miles 

 of the marsh than to new waters beyond that range. I presume that most 

 such pioneers are young birds approaching their first breeding season. 

 Pioneering does not contradict the homing behavior of young females that 

 may establish themselves near their natal marsh or in an area learned dur- 

 ing juvenile wanderings. 



The story of the Gadwall, on the other hand, shows breeding populations 

 and probably recent pioneerings on the Atlantic Coast, far from the major 

 nesting range, which lies northwest of the Mississippi Valley (Griffith, 1946). 

 Certainly the new nesting groups of this species on Long Island (Sedwitz 

 et ah, 1948) and in Maryland (Springer and Stewart, 1950) are pioneer- 

 ings. Most of these records are for refuge marshes, where nesting conditions 

 have been made favorable for the species and where shooting has been con- 

 trolled. Robert A. Wells writes me that there are recent pioneerings of the 

 Ring-necked Duck in small lakes of the Adirondack Mountains, the bird now 

 breeding on waters where it was unknown before. 



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