TRAVELS OF WATERFOWL 



to their respective urges. She must direct this response to the proper destina- 

 tion: lakeshore, slough, or meadow. Since (as holds for some hens on their 

 loafing places ) she cannot see any of these destinations, it must be assumed 

 that when she directs her movement toward the proper goal, she does so 

 on the basis of past experience. Her destination is not in sight, but her flight 

 goes in the proper way. Past experience guides present action to carry her 

 to the unseen future. Without such preselection she could not move pre- 

 cisely, as we see she does, to the goal the inner stimuli direct her to attain. 

 All three destinations are familiar places, but none can exist to her in the 

 present because each place is beyond eyesight. Thus there must be a flow 

 of continuity not only from the past to the present but projected into the 

 immediate future. 



The same continuity of action from the past into the future may be seen 

 in Mallards flighting to stubble. When they depart from the lakeshore at 

 dawn, the path of their travel from the very beginning leads them to a par- 

 ticular destination which must have been selected when the journey began. 

 The field is a prospective factor for these birds ; physically it can exist only 

 in their future because it is several miles beyond their eyesight, hence the 

 field cannot be a part of their present. Yet somehow the place lives in these 

 Mallards' present at the time of departure, or how else could they make the 

 direct and orderly journey? Retentiveness gives duration to life, "the con- 

 tinuous progress of the past which gnaws into the future" (Bergson, 1911a). 



Once more we come to that indefinite boundary between science and 

 philosophy. Lashley (1950) points out that in the three hundred years 

 since Descartes's attempt to explain memory in terms of the action of the 

 brain "much has been learned concerning the nature of the impulses trans- 

 mitted by nerves. Innumerable studies have defined conditions under which 

 learning is facilitated or retarded, but, in spite of such progress, we seem 

 little nearer to an understanding of the memory trace than was Descartes." 

 Somehow, quite beyond our understanding, there are within and as a part of 

 each bird all the phases of its life story : the places and the companions near 

 and distant both in time and in space, its mother, its first home, its mate, 

 its nest, its home range and territory, its molting place, its wintering area. 

 However alike two ducks may be in their physical structure, however simi- 

 lar may be the innate behavior of one duck to that of its specific compan- 

 ions, each individual bird is different from all others of its kind by virtue 

 of its unique experiences. 



54 



