170 



The Bird 



windpipe, and the effect is heightened by the rings which 

 extend as far as the lungs, which are half-rings or semi- 

 circles, the inner halves being replaced by membrane. 

 This organ is peculiarly characteristic of birds, there 

 being not a trace of it in any reptile. 



But though the syrinx alone is concerned in the pro- 

 duction of sound, this may be modified, made resonant, 

 or given a reverberating quality by a special structure 

 or by windings of the trachea before it reaches the syrinx, 

 and which are perfect analogies of human musical instru- 

 ments. Many species of ducks have an enlarged box of 

 bone, a kind of drum, on the lower portion of the trachea, 

 sometimes of one shape, sometimes of another, serving, 

 doubtless, to give power to the bird's voice. Cranes and 

 swans have veritable French horns in their breast-bones. 

 The windpipe enters between the arms of the clavicles 

 or wish-bone, and describes an S or even a more intricate 

 figure before passing out and dividing into the two bronchial 

 tubes. When a Trumpeter Swan stretches out its neck 

 and utters a musical clang, most maligned by comparing 

 it to a whoop, we should remember the cause of its mellow- 

 ness. In the majestic Whooping Crane of our Western 

 States, which in a few years will have vanished from the 

 earth, the windings of the trachea reach their maximum. 

 The entire windpipe of this bird is four feet in length, and 

 of this, one-half is coiled within the sternum, or breast- 

 bone, giving remarkable volume and resonancy to the 

 voice. 



