IOTERTNE WARBLER 



respects does it differ? The song at least bears no resem- 

 blance to that of these other species ; it is a highly specialized 

 production, abounding in peculiar phrases and combinations 

 which appeal to the human ear, and the power of imitation 

 seems to be highly developed. The most interesting feature 

 of its vocal development is the remarkable similarity between 

 its true song and that of the Marsh Warbler; in fact the 

 resemblance is so great that one may readily fail to identify 

 the owner of the voice. The songs of both species rank high 

 in any scale of vocal development, and it is possible — though 

 I cannot speak with any great authority on this point — that 

 the power of imitation possessed by the Icterine Warbler is as 

 great as that of the Marsh Warbler. It is clear from the 

 casual observations which I have been enabled to make from 

 time to time that the bird stands high in the scale of 

 emotional development ; the conflicts, the restless movements, 

 the passionate uttering of the song into which is infused much 

 feeling tone, all betray that excitable condition of the nervous 

 system which, judging by experience, leads to interesting 

 behaviour in many directions. 



