INTRODUCTION 15 



the Canary Islands, for instance, have acquired a 

 much longer and desultory song than is heard from 

 this species elsewhere. The late Lord Lilford has 

 recorded an instance of very peculiar variation in 

 the song of the Robin. It is also rather difficult to 

 say what is real variation in a song, or what may be 

 due purely to imitation. Mr. C. A. Witchell in his 

 little work entitled The Evolution of Bird Song, 

 has recorded a great many instances of what he 

 considers legitimate imitation. But we think he 

 assumes too much, and that a great deal of what he 

 attributes to an imitative faculty is nothing but a 

 similarity of coincidence ; whilst we cannot refrain 

 from saying that this author should have been more 

 careful to acquaint himself with what other natural- 

 ists have already written and suggested before 

 making so many dogmatic statements, or claiming 

 as novelty much that had long been published. 

 And here we may repeat what we wrote several 

 years ago on yet another branch of this intensely 

 interesting subject : The standard of perfection or 

 excellence in the songs of birds is by no means an 

 uniform or constant one. This is especially remark- 

 able at the period when a species resumes its voice 

 after a long interval of silence, and in the maiden 

 efforts of young indivfduals. Any moderately 

 observant person may remark innumerable instances 

 of this peculiarity in every singing species. Look- 

 inor throuo-h our note-books we find many observa- 



