Are Birds Singers or Whistlers? 179 



First, it is unreasonable to suppose that the rich, loud, 

 clear notes of the thrasher, the cardinal, and the mocking- 

 bird, lilting across the fields and capable of being heard 

 a long distance, are generated far down in the lyrist's 

 chest by the vibrating of the margin of a tiny mucous 

 membrane. If it had its genesis there, it surely would 

 display a muffled or guttural or sepulchral quality. In 

 the second place, it has been proved by actual dissection 

 that the shrike, which possesses no song gift worthy of 

 the name, has a well-developed syrinx, while the mocking- 

 bird, our feathered minstrel par excellence, has a syrinx 

 that is absolutely insignificant. On the other hand, the 

 shrike's larynx, including the glottis, is a clumsy affair, 

 whereas the mocker's larynx is indeed wonderfully made. 



It must not be supposed, however, that the syrinx does 

 not perform an important function in the production of 

 avian melody. It acts as a regulator or meter of the air 

 impelled from the lungs. By means of -the folds or mem- 

 branous valves the mouths of the bronchial tubes may be 

 opened widely or almost closed, and in this way, to quote 

 from Mr. Thompson, " the bird is enabled to measure in the 

 nicest manner the amount of air thrown from the lungs 

 into the trachea." In producing a staccato, for example, 

 the valves flop up and down, doling out the air at the 

 proper intervals and in precisely the right quantities. 



Indeed, nothing in the world of Nature is more won- 

 derful than the gift of bird song, and nothing proves 

 more clearly the doctrine of design, or, at least, of adap- 

 tation to a specialized purpose. 



