Page:The British Warblers A History with Problems of Their Lives - 9 of 9.djvu/29

 respects does it differ? The song at least bears no resemblance 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.