220 THE STORY OF THE BIRDS 



aesthetic human tastes as well as to their own 

 pleasurable or passionate gratification. It is 

 not within the scope of the present volume to 

 describe in detail the songs of the various species, 

 but before leaving the subject we ought perhaps 

 to call attention to the fact that the action of 

 birds during the utterance of their music varies 

 considerably. Some species invariably sing 

 whilst standing at rest, others when skipping 

 to and fro in frantic joy, others when soaring 

 or flying, others yet again accompanying their 

 melody by a more or less display of plumage, 

 or muscular action of the wings and tail. 



We now pass to a consideration of certain 

 vocal sounds, none of which reach the human 

 standard of a song, appealing to no human 

 taste as the exquisite melody of song uni- 

 versally does ; many of them to our ears being 

 most discordant, impressive, curious, or startling, 

 though possibly appreciated by the sex to which 

 in a great many cases they seem specially to be 

 addressed. Sometimes they sound the signal of 

 defiance, or the invitation to the fray. In a 

 scientific sense these strange sounds, when uttered 

 under the influence of love or passion, must all 

 be classed as music or song. The familiar note 

 of the Cuckoo, for instance, is confined to the 



