56 
CHAPTER IY. 
Organs of Sound. — Ducks, Crane, Goat-Sucker, Bell-Bird, etc. — 
Distance at which Sounds may be heard. — Plumage. — Struc- 
ture of Feathers. — Goose-Plucking. — Summer and Winter 
Plumage. 
TP BOM 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 ex- 
plained by comparing them with the organs of sound in the 
uman species. We utter sounds, and speak, through a 
certain tube, communicating 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 windpipe; 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 notes this 
simple pipe is capable of producing. A good deal depends 
i 
