146 IDLE DAYS IN PATAGONIA 



scream or call that may be heard a distance of two 

 or three miles to the faintest tinkling or lisping 

 note that might be emitted by a creature no bigger 

 than a fly, there is a certain aerial quality which 

 makes them differ from all other sounds. Doubt- 

 less several causes contribute to give them this 

 character. There is the great development of the 

 vocal organ, which makes the voice, albeit finer, 

 more far-reaching than that of other creatures of 

 equal size or larger. The body in birds is less 

 solid ; it is filled with air in the bones and feathers, 

 and acts differently as a sounding board ; further- 

 more, the extremely distensible oesophagus, al- 

 though it has no connection with the trachea, is 

 puffed out with swallowed air when the bird emits 

 its notes, and this air, both when retained and 

 when released, in some way affects the voice. 

 Then, again, the bird sings or calls, as a rule, 

 from a greater elevation, and does not sit squat, 

 like a toad, on his perch, but being lifted above 

 it on his slender legs, the sounds he emits acquire 

 a greater resonance. 



There are bird sounds which may be, and often 

 are, likened to other sounds ; to bells, to the clang- 

 ing produced by blows on an anvil, and to various 

 other metallic noises; and to strokes on tightly- 

 drawn metal strings; also to the more or less 

 musical sounds we are able to draw from wood 

 and bone, and from vessels of glass by striking 

 them or drawing the moistened finger-tips along 

 their rims. There are also sounds resembling 



