92 THE STORY OF BIRD-LIFE. 



bine into one there is fixed a tiny elastic mem- 

 brane, which serves the same purpose as a reed, 

 and sets the air vibrating in the pipe which 

 corresponds to the pipe in the oboe, i.e., the 

 bird's windpipe. We are apt to fancy that the 

 bird sings with his bill or his tongue, but this 

 is altogether a mistake. . . . These may have 

 some kind of influence upon the sound, but that 

 sound is produced far down in the bird's throat, at 

 the thin end of the tube, just as it is in the oboe." 

 "In the oboe the tube is of wood, and there- 

 fore hard and inelastic ; of itself it cannot alter 

 the pitch of the sound produced by it, but, in 

 order to alter the pitch, holes have been punched 

 in the tube by stopping which with the fingers you 

 can make the vibrating column of air in the tube 

 longer or shorter at will, and thereby alter the 

 pitch of the sound ; just as in the trombone 

 the same thing is effected by moving one tube 

 up and down within the other." 



" In the bird's instrument the tube is not hard 

 or stiff. ... It can be lengthened and shortened, 

 squeezed and relaxed, by many strong muscles 

 which are attached to it ; and these give the bird 

 A capacity ... of producing an almost endless 

 variety of pitch. ..." 



Many birds have exquisitely beautiful notes, 

 but they are nevertheless not to be confounded 

 with song. Our English cuckoo, for instance, 

 has no song. The well-known notes so dear to 

 us all are to be regarded as call-notes intended 

 to give. notice of his whereabouts to his mate. 

 So again the piping of the curlew and many 

 other water-birds are not songs, but call-notes. 



