TRADITIONS OF WATERFOWL 



most of the continent. Most of the rest are divided into several subspecies, 

 and some, like the Song Sparrow, show abundant racial variation. This 

 point is important to our thesis because it appears that, within certain 

 limits, ecological patterns as well as geographical locations are the tradi- 

 tional birthright of subspecies whose distribution is limited to certain hab- 

 itats. Marshall (1948:252) says (in reference to races of the Song Sparrow 

 in the San Francisco Bay area) that "habitat preferences, based merely on 

 the impulse of the individual to stay in the kind of environment in which 

 it was raised and with which it is familiar," may serve to effect the eco- 

 logical isolation of a race; and that "it should be evident that such prefer- 

 ence would be unlikely to be fixed genetically." It seems to me that Marshall 

 has neatly expressed this fine difference between the inborn and the non- 

 heritable response to the environment. At Delta some Song Sparrows live 

 their whole reproductive lives in stands of Phragmites far from shrubby 

 edges. But close by, and over much of the prairie country, other Song Spar- 

 rows (which taxonomists recognize as the same subspecies) nest in brushy 

 edge cover. This local variation in breeding area I take to be the nonheredi- 

 tary habitat preference to which Marshall refers. It is interesting to note 

 that since there are no outstanding singing posts in the Phragmites, the 

 males with marsh territories regularly make towering song-flights, which 

 are not characteristic of nearby shrub-dwelling Song Sparrows. 



The same sort of thing is seen in ducks. On the Delta Marsh the pre- 

 ferred nesting of the Canvasback is bulrush, but in the pothole country 

 around Minnedosa many Canvasbacks nest in cover types entirely unlike 

 anything used by the species at Delta. The nesting habitat of Pintail and 

 Mallard in the farming country of Manitoba is quite different from the 

 nesting environment of these species on the treeless plains of Alberta. In 

 Manitoba the Canada Goose nests on fish boxes mounted on poles at Ren- 

 nie, on open islands at Dog Lake, and on Muskrat houses at Delta. 



Waterfowl and many other birds apparently have an inborn urge for 

 the homeland of birth, where each individual selects the environmental 

 patterns most closely meeting its innate breeding requirements. From this 

 instinctive attachment to home may arise the isolation upon which mor- 

 phological variations are founded, even in the absence of geographical bar- 

 riers to the flow of genes. However innate the homing behavior, the geo- 

 graphic place of home is inherited, not genetically, but by birthright and 

 experience. 



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