LEARNED RESPONSE TO THE ENVIRONMENT 



female Mallard. Such individuals no doubt have lived with Mallards, thus 

 having learned to associate this series of notes with a favorable situation. 



It is essential that we understand the limits of this "language." This is 

 not communication as we know it in our highly articulate human inter- 

 course. The call of a bird is an innate vocal response to certain stimuli. These 

 may be inner stimuli, such as are induced by hormonal changes in the 

 sexually active bird. Or the responses may be to outer stimuli, such as the 

 presence of food or enemy. The voice is merely the inborn response to a 

 condition or situation. The reaction on the part of the companion, whether 

 innate or learned, is an answer to an outer stimulus, the note heard. Full 

 response, however, depends upon inner forces. A passing Mallard may not 

 come to the feed call unless the stimulus of an empty gizzard directs it to 

 respond. The Canvasback hen does not respond to the courting note of a 

 Canvasback drake unless her position in the sexual cycle so directs her. 



An insight into the operation of the avian vocabulary may be had, I be- 

 lieve, by drawing an analogy from human behavior. Baby tumbles down 

 the steps and immediately begins to cry. The crying of the infant is not 

 consciously directed toward the parent; the situation demands that the 

 baby cry and it cannot avoid the act. The child's mother responds by run- 

 ning to the scene of the accident, directed there by the child's voice and 

 her parental drive. The voice in ducks is similar to the cry of the injured 

 human infant in that it identifies the individual and it may also identify the 

 situation and the condition; but the voice does not consciously convey a 

 message. 



Certain sounds, not vocal, which are related to functional movements, 

 may serve as signals. I have lured Mallard, Gadwall, and Blue-winged Teal 

 into a dense stand of bulrush by swishing my hand in the water to simulate 

 feeding sounds. Martin Bovey told me that on the Currituck Sound he saw 

 a guide bring Lesser Scaup to his stool on a calm day by sloshing his feet 

 in the water. There are reactions to certain sounds that are not to be ex- 

 plained. This morning three White-winged Scoters slipped by me at a dis- 

 tance of five hundred feet, heading pell-mell for the open lake. I gave a loud 

 yell and immediately the band turned to fly back over me. Forbush (1925: 

 276) tells how hunters along the New England coast bring these Scoters 

 within gunshot by firing a charge or by shouting from a dory. I have seen 

 Lesser Scaup and Green-winged Teal swing back over my blind when I beat 

 the paddle sharply on the side of the canoe. A quick wave of the hat or a 

 kick of the boot sometimes serves to turn a flock into the decoys. This might 



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