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CHAPTER IV. 



ORGANS OP SOUND. DUCKS, CRANE, GOAT-SUCKER, BELL-BIRD, 



ETC. DISTANCE AT WHICH SOUNDS MAY BE HEARD 



PLUMAGE. STRUCTURE OP FEATHERS. GOOSE-PLUCKING. 



SUMMER AND WINTER PLUMAGE. 



FROM the organs of breathing we naturally proceed 

 to those of voice. The striking difference existing 

 between those of birds and other animals, may, 

 perhaps, be best explained by comparing them with 

 the organs of sound in the human species. We utter 

 sounds, and speak, through a certain tube, comrnu- 

 nicating from the mouth to the lungs, called the 

 trachea or windpipe, which is furnished with very 

 beautiful contrivances for the purposes of sound. 

 In like manner, birds are provided with windpipes; 

 but, unlike men and animals, they have a double set 

 of instruments, if they may be so called, one at the 

 upper, and the other at the lower end of the wind- 

 pipe ; and as it is in the lower part of the windpipe 

 chiefly that the peculiar contrivance for uttering 

 sounds is to be found, which may be compared to 

 a clarionet, or similar musical instrument, it so 

 happens, strange to say, that a bird might utter 

 notes even after its head was cut off. It is astonish- 

 ing what powers. and varieties of notes this simple 

 pipe is capable of producing. A good deal depends 

 on the construction of the windpipe itself, and 

 several, as the Duck tribe, are very curiously formed. 

 It usually consists of a straight tube, of a stiff horny 



