AWARENESS OF DIRECTION 



In the flow of life, a bird faces familiar places on all sides. The direction 

 in which the bird moves, that with the greatest valence, depends upon 

 the appetites impelling travel. On the local range the bird may go toward 

 nest, gravel bar, or slough according to the stimuli of oviduct, gizzard, or 

 crop. In the same manner, the Manitoba Mallard hen wintering in Texas 

 must be driven by her newly awakened sexual appetites to respond to her 

 awareness of the direction toward Manitoba. We do not know what appe- 

 tites awaken an awareness of familiar wintering places in autumn. But in 

 each of these situations where migration is concerned, the valence of cer- 

 tain directions depends upon appetitive behavior, and the travel of migra- 

 tion differs from movement on the home range only by the relative meas- 

 ures of time and space. 



Where waterfowl migrate homeward along flight lines of standard di- 

 rection, we see great numbers going the same way ; but the travel is not to 

 a common destination. The spring navigation homeward (except for the 

 mated drake, or the young of geese and swans) is an individual problem 

 which must be faced separately by each bird. The female duck may start 

 from Texas with many others of her kind, but eventually there comes a time 

 when she, like each companion, must bend away from the direction of the 

 group and take her own course to the familiar nesting place. Leadership 

 in spring migration cannot be entrusted to casual companions, or else the 

 arrival home would be a remote chance indeed. 



In the same way, molting movements of adults and the swift, direct 

 passage of mass fall migration hinge upon an awareness of direction toward 

 destinations that have been visited before. But in these nonsexual migra- 

 tions, the whole body of birds moves together as a social group to the 

 common destination without the requirement of individual separation. 



To understand this awareness of direction, as it is cued by the sun and 

 by the surrounding world, would be to understand how the duckling learns 

 to know its mother, or how it so rapidly takes its familiar place within the 

 complex range of its natal slough. The evidence suggests that each bird 

 gains familiarity with its mother, with its home pond, and with the great, 

 wide world beyond, by virtue of its experience; but to explain this process 

 of rapid learning and retentiveness would be to unravel the whole mystery 

 of memory itself. 



Such awareness of direction founded upon experience is, of course, thin 

 soup for those who fail to distinguish between the orientation of adults 



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