CHAPTER IV. 



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. 



T^ROM 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 ftf notes this 

 simple pipe is capable of producing. A good deal depends 



u3S3&S^ 



