Figure 20. Dispersal of young ducks of seven species (Mallard, Gadwall, Pintail, Blue- 

 winged Teal, Shoveller, Redhead, and Canvasback) from the pothole breeding grounds 

 of South Dakota. During the summer of 1954 flightless ducklings were banded on their 

 home marshes. Spots show where they were shot during October and November of 

 their first autumn. Ray Murdy, who supervised this banding program, points out that 

 although the dispersal is random, there is a bias toward the north, east, and south, where 

 the habitat is more favorable than on the dry plains to the west. Not all birds cleared 

 away from their birthplaces by the opening of the shooting season, and about one-half 

 of the returns are from youngsters killed in their home country (large black circle). 

 (This figure is presented through the courtesy of the South Dakota 

 Department of Game, Fish, and Parks.) 



wanderings hinges, of course, on the time and the latitude of birth. Young 

 Pintails, some of which are on the wing at Delta by the last week in June, 

 have more time to explore than young Delta Canvasbacks or Redheads, 

 which seldom are in the air before August. Redheads hatched in Utah have 

 far more time to roam than their kin which enter the world in Yukon Ter- 

 ritory. Some late-hatched young have no time at all to stray before the 

 arrival of frost, and a few individuals, especially in the diving ducks, never 

 reach flying stage before the arrival of ice. 



No doubt one of the functions of juvenile travel is the refinement of 



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