THE VISUAL WORLD 



stubble every evening along the same creek bed, we judge that they are 

 aware of the terrain, just as they are of the narrows between two lakes 

 which they cross regularly. When the drake holds close to his mate through 

 all the days of migration, we conclude that he perceives in her some char- 

 acter that distinguishes this particular hen from all others. When the Can- 

 vasback hen finds the way through the tules to her nest, she must be aware 

 of environmental patterns. 



"The important thing to realize," says Russell (1934:181), "is that the 

 animal's perceptual world is essentially a practical or functional one. The 

 animal attends to, perceives, and shows behavior in respect of, only those 

 events, objects and characters of objects that are at the moment functional- 

 ly important to it, those about which it is impelled to do something; only 

 these have valence for it." Such valence * hinges on the condition of the 

 bird: on its age, its sexual status, the time of the day and the time of the 

 year. The mother is valent for the ducklings only during the period of 

 growth, the nesting cover has valence for only the nesting hen, and she has 

 valence for her drake only a part of the year. 



Some components of the environment must have valence because of 

 the innate make-up of the bird. In our captive ponds are Canvasbacks and 

 Pintails that have been hatched together and raised as companions in the 

 same pens. Until nearly a year old they share this captive environment. 

 When May arrives, however, the Canvasback hens select emergent vegeta- 

 tion for nesting cover, while the Pintails walk up on the dry ground to seek 

 out nesting places in grass some distance from water. Such selection follows 

 the visual inspection of the entire landscape, of which a part is perceived 

 as the place for nesting, the choice between emergent and upland cover 

 being inborn. When young hand-reared Mallards are released to the wild, 

 they soon seek out the part of the landscape that is their never-before-seen 

 birthright. Set free in the grassy thickets behind the lakeshore, they soon 

 move to the emergent beds of bulrush at the shoreline shallows. 



This seems a simple shift, and yet it does represent a choice between 

 favorable and unfavorable environment that is not based on experience. 

 Our Pintails and Mallards seek out the rushy borders when given freedom, 

 but the young Redheads and Canvasbacks go to the open water that is the 

 natural haunt of their wild brethren. In his studies of ducklings ( 1951 : 167) 

 Fabricius found that "the newly hatched birds showed some apparently 



"Russell (1934:179) considers as "valent, or possessing valence, those objects, or char- 

 acters of objects, and those events, in the perceptual world of an animal, in respect of which 

 it shows behavior." 



