The nesting habitat of Mallard and Pintail on the treeless plains is nothing 

 like the environment used by these species in Manitoba. 



occurs in ducks. Taxonomists recognize the Coots nesting in Ontario as the 

 same race that breeds in California. 



The weight of the discussion has been placed on waterfowl, which, it 

 must be acknowledged, have patterns of behavior quite different from those 

 of many other kinds of birds. For example, the family unity in migration, 

 which builds such strong traditions for the geese and cranes, is found only 

 in a few other groups. Not many species accomplish their pairing in gre- 

 garious winter companies, as do the ducks. More typical is the behavior 

 of the passerines, in which the family usually dissolves soon after the young 

 are able to take care of themselves and in which pairing takes place at or 

 near the nesting area, often on the territory proclaimed by the male before 

 the arrival of the female. The tradition of birthright is strong in such birds, 

 however, as both sexes migrate back to breed near the place of youthful 

 experiences. Thus a wide gene-flow from one region to another is prevented. 



In these migratory perching birds there are only a few, such as the 

 Magpie and the Barn Swallow, that have one geographical race spread over 



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