The grain fields are a world unknown to these young Mallards, 

 as unreachable as the moon. 



some other distant land; by the end of its first year it has experienced half 

 a continent. Where, as this circle of experience grows outward from the 

 natal slough, is the dividing line between proximate and distant orientation? 

 So, as its life develops, the young duck gains within a few weeks after 

 birth a traveler's perspective of the world that man could not achieve 

 through all the eons of his existence until this present moment of history. 

 Not until he understood the relativity of motion, nor until he had viewed 

 the earth as an airman, could man comprehend the world as a bird awing, 

 or understand how the realm of migration, like the narrow home range, be- 

 comes familiar through the experience of travel. 



Although a bird comes and goes about a range that is familiar to it, 

 there is evidence of Type II navigation, where a direct course is followed 

 in the absence of landmarks to guide the way. Kramer (1951, 1952) has 

 shown how the sun serves as a cue to compass direction. Studying the ac- 

 tivity of caged Starlings, he found that during the migration season, their 

 movements had a strong bias in one direction, and this orientation de- 

 pended upon the sun. Such solar influence was tested by manipulation of 



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