BROKEN TRADITIONS 



it is possible that populations of more southern marshes might show a simi- 

 lar capacity to expand when more ducks are available. In 1951 the Waubay 

 pothole region of South Dakota held 124 ducks per square mile (Evans, 

 Mann, and Black, 1951:162), a resident breeding population five times as 

 dense as that of the similar Canadian pothole country in 1947. In 1950 the 

 State of North Dakota held a nesting population averaging 19.7 ducks per 

 square mile, a number greater than the over-all average for Alberta (11.5 

 ducks per square mile) (Hjelle, 1951:149; Smith, 1951:30). I suspect that 

 the breeding grounds in the true prairie country of the Dakotas, Minnesota, 

 Wisconsin, and Manitoba may serve as security range during seasons when 

 parts of the more western plains dry out to the point of being untenable to 

 nesting ducks. This does not imply that birds move east to breed success- 

 fully the first year of a drought; but during dry periods lasting several years, 

 the marshes of the true prairie hold water longer, then providing the main 

 part of the breeding grounds in the middle latitudes. 



I have spoken mainly of the United States breeding grounds of the 

 north central region because they are potentially so fine and so immedi- 

 ately threatened by 4 drainage. There are other great breeding ranges in the 

 United States, such as the sandhill country of Nebraska, the plains of Mon- 

 tana, the Great Basin country of Utah and Idaho, and the marshes of the 

 Klamath basin of California and Oregon, to mention only a few. Some of 

 these western ranges not only have many species of game ducks, but are 

 heavily productive of Canada Geese. If we are to plan for the wildfowling 

 of the future as carefully as we plan for barley, we must count heavily on 

 these breeding grounds within the settled regions of North America. 



In token of the importance of this resource, a technical program for 

 waterfowl investigations has been launched far and wide across the land. 

 At last we have grasped the idea that we cannot manage waterfowl as a 

 renewable resource unless we know more about ducks and geese, species 

 by species, region by region. And during the past ten years we have learned 

 more about these birds than in all our previous history. University gradu- 

 ate departments, biological stations, provincial and state game branches, 

 and central government agencies are studying waterfowl in many ways 

 and in many places. Some seek to understand such fundamental problems 

 as the natal range of ducklings in Manitoba (Dzubin, 1954), or the effect of 

 spring rainfall on nesting Mallards in California (Mayhew, 1955). Others 

 set about to find ways of restoring birds to new or empty ranges, as by 

 transplanting flightless juveniles from old to new marshes (Wells, 1954; 



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