78 THE STORY OF THE BIRDS: 
No other creature has a throat like a bird. It has 
placed its singing apparatus at the forks of its 
bronchial tubes, and left all the rest of its vocal cav- 
ity to modulation. The greatest prima donna has no 
such instrument to play upon. 

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Nightingale. 
True bird music has developed solely within the 
birds, for the lower birds have not the modulating 
apparatus that the higher or oscine kinds have, there 
being a great difference in kind and number of mus- 
cles, which we can not discuss here. The lower birds 
with down on their nestlings can (usually) scream or 
squeak only, or at best issue a pleasant, slightly mod- 
ulated whistle. 
Song, therefore, is largely an invention of bipeds, 
