TRAVELS OF WATERFOWL 



come to this stool. I (and many other hunters) have resorted to methods 

 even cruder than this. On the lakeshore I have formed duck-sized mounds 

 of sand in the shallow water. The sand is too soft to be arranged in true 

 duck form: these are merely small oval mounds placed in loose formation 

 with most of them pointing into the wind. This fools no duck in daylight; 

 but in the same evening light in which the spring drake distinguishes an 

 intruder from a migrant, I have seen autumn Mallards swing in close to my 

 sand decoys and even alight amongst them. Where the Lesser Snow and Blue 

 Geese fly in autumn, hunters often bring them into gun range with news- 

 papers or white rags tied to little sticks arranged in flock formation. 



Lorenz (1937:247) found that his tame but free-living Jackdaws would 

 attack him furiously when he carried a black bathing suit in his hand and 

 that "anything glistening black and dangling, carried by any living creature 

 would release the very same reaction in the Jackdaws. ... In a bird that 

 readily recognizes and discriminates fellow-members of the flock, it is 

 rather surprising that the process of releasing the social defending reaction 

 so closely resembles that which elicits the responses of lower organisms. 

 ... An instinctive reaction of survival value, when directed exclusively to 

 a particular object, may be released as if through a surprisingly small choice 

 among the large number of stimuli normally emanating from the object." 

 The white of small rags arranged in flock formation is sufficient to release 

 the gathering behavior in traveling Blue and Lesser Snow Geese, bringing 

 them within range of hunters' guns. The white of the rags is a "key-stimu- 

 lus"; and all such colors or plumage patterns, structures or actions, that 

 draw responses from social companions, Lorenz ( 1937 ) has termed releasers 

 (Ausloser). (See also Baerends, 1950 ; Tinbergen, 1951.) 



It is very interesting that the female Pintail, which distinguishes her 

 drake from all other males, does not perceive differences between her own 

 eggs and stones or wooden eggs placed in her nest (Farley , 1939:57; Sowls, 

 1955:103). Even though the stones are seen several times a day, the hen con- 

 tinues to incubate, satisfied with the "feel" of the small rocks under her breast. 

 Perception of the visual world may be conditioned by learning and ex- 

 perience. The Mallard drake has an innate awareness of certain sexual ac- 

 tions of the Mallard female, but he must learn the identity of his own sexual 

 partner. The duckling must learn its parent. The female may be innately 

 attracted to a certain type of nesting cover but she learns to find the place 

 of her nest. I believe that each duck learns to perceive characteristics in the 

 landscape as guides to orientation. The large meadow meets the innate nest- 



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