* *■ 





The first Pintails are on the wing long before the oldest 

 Canvasback youngsters take flight. 



flight technique; another is the strengthening of the flight muscles. After 

 watching the young color-banded ducks at Delta, I am sure that at least 

 three or four weeks must pass before the youngsters lose their awkwardness 

 on the wing. And the effect of flight on the wing muscles themselves is 

 evidenced by the changes in size and in the color of the flesh. 



There is a universal urge for juveniles to use their wings ; and once in 

 the air, they move out and away from home in what Thorpe ( 1951a:24) con- 

 siders a "general curiosity about the environment." There is among juveniles 

 "an aggressive behavior," says Kalela (1954:24), "commonly shown by birds 

 when they leave their parents, and this leads to the development of undi- 

 rected wanderings . . ." Here, once more, we find an exception in the geese 

 and swans, and also in the cranes, in which the family remains united in its 

 first flights and there is no aimless wandering of the young. This family 

 grouping also holds with a few passerines. In Manitoba the Arkansas King- 

 birds move away from the nesting locality in family units a few days after 

 the young can fly. For a short while afterward these family groups may be 

 seen scattered widely on roadside wires, the parents still attending the 

 young; then in two or three weeks they are all gone, not to be seen again 



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