"There are few aspects of animal behavior that have 

 been more neglected by present-day zoologists than 

 learning, which we may provisionally define as that 

 internal process which manifests itself as adaptive 

 change in individual behavior as a result of experi- 

 ence." W. H. Thorpe (1950:387) 



Learned Response to the Environment 



The system of aerial trails about a duck marsh 

 is evidence that waterfowl react positively to their environment. What is 

 behind this response to their surroundings? Is this rigid, set, innate be- 

 havior? A downy Canvasback less than a day old benefits from neither past 

 experience nor parental guidance when it first takes to water ; it swims with- 

 out an intervening period of learning. Thenceforward throughout its life as 

 a duckling and as an adult, its activities are directed primarily toward its 

 aquatic world. In flight the duck's movements are physically unbounded; it 

 is free to go where its wings might take it. Yet its aerial journeys are re- 

 stricted largely by the pattern of water on the earth below. Hence, in its 

 selection of trailways about a marsh, a duck may be following, in large 

 measure, an inborn attachment to water. 



We must believe, however, that adherence to regular flight trails and 

 passes is far above the level of purely inborn behavior. This we know to be 

 true because the trail has its beginning and end; a duck departs from a 

 special place and arrives at a particular destination. The starting point, the 

 trail, and the destination vary with individuals and with groups; different 

 birds or flocks select different starting points, trails, and destinations, and 

 these are always small parts of a complex landscape. Such travel cannot 

 rely on innate behavior alone. The loafing spots, the feeding places, and the 

 trails must be found, either by exploratory movements or by following the 

 actions of experienced companions. In other words, the feeding and loafing 

 places are learned, and the trails between these are learned routes. A duck, 

 then, is innately attracted to its special environment, but it learns its posi- 

 tion within that sphere. 



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