TRAVELS OF WATERFOWL 



Manitoba Game and Fisheries Branch, that same afternoon watched the first 

 members of the mass migration arrive over the Netley Marsh (68 miles east 

 of Delta ) at exactly the same minute. 



We can hardly speak of time without considering the bird's orientation 

 in space. Waterfowl are visually oriented to their environment, having 

 learned their place in the world by sight. The channels, passes, leads, and 

 chains of sloughs are followed as they are seen; passes are used again and 

 again because they are learned. No duck, of course, lives on the same home 

 range or even on the same marsh through all of one season. The breeding 

 territory is distinct from the rearing place; there is the molting marsh and 

 there are still other zones of late summer activity. The first move of a bird 

 to a new place is a pioneering venture, albeit this trip may be made with 

 experienced companions. Once settled on a fresh range, the bird learns the 

 new area and is ever linked (so the evidence of banding tells us) to this 

 region of experience. The thread of continuity from range to range strength- 

 ens as experiences are repeated ; this explains the tendency of waterfowl to 

 revisit the same areas year after year. 



The importance of eyesight in spatial orientation is evidenced by the 

 relative heights of travel. Where the distance is short, as when Mallards fly 

 from the Station pond to the bay edge, travel is low. Where the distance is 

 greater, as when they fly to the far shore of the bay, the altitude of flight is 

 increased, and stubble birds on the way to the prairie go still higher. 

 Travelers to nearby fields fly at the edge of gunshot range, around two 

 hundred feet, but Mallards going ten or fifteen miles travel more than twice 

 as high as that. Rowan writes me that he and his hunting partner have 

 "always taken altitude as a direct indication of distance and have regulated 

 our gunning accordingly. The correlation is very marked." In his studies 

 of the Canada Goose in Missouri, Lewis G. Helm (letter) saw a direct rela- 

 tion between length and height of travel, the birds rising higher as the 

 distance of daily feeding flights increased. 



The bird on its home range is aware of its position not only through 

 what it immediately sees, however, but through the retention of previous 

 experiences there. In short, the duck is oriented not only to the space of 

 the present, but to this as related to places of past experience. The orienta- 

 tion of the moment is not only to the surroundings seen, but to places over 

 the horizon beyond the edge of visibility. Dr. A. A. Alford and I observed 

 Mallards and Pintails making daily feeding flights to flooded fields south of 



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