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CHAPTER IV. 
ORGANS OF SOUND. — DUCKS, CRANE, GOAT-SUCKER, 
BELL-BIRD, ETC. DISTANCE AT WHICH SOUNDS MAY 
BE HEARD. PLUMAGE. STRUCTURE OF FEATHERS. 
-GOOSE-PLUCKING. SUMMER AND WINTER PLU- 
MAGE. 
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, he best explained by comparing them with 
the organs of sound in the human species. We utter 
sounds, and speak through a certain tube, communi- 
cating 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 astonishing 
what powers and varieties of note this simple pipe 
is capable of producing. A good deal depends on 
the construction of the windpipe itself, and several, 
as in the Duck tribe, are very curiously formed. 
It usually consists of a straight tube, of a stiff horny 
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