180 Habit and Instinct. 



thrushes always, and the linnets for the most part, sang 

 true, imitating the song of their own kind. Couch, in hi& 

 " Illustrations of Instinct," * says that he knew a gold- 

 finch, which had never heard the song of its own species, 

 nevertheless singing this song, though tentatively and 

 imperfectly. And speaking of the Dartford warbler, Colonel 

 Montagu says f that young males brought up from the 

 nest "begin to sing with the appearance of their first 

 mature feathers, and continue in song all the month of 

 October, sometimes with scarcely an intermission for 

 several hours together. The notes are entirely native, 

 consisting of considerable variety, delivered in a hurried 

 manner, and in a much lower tone than I have ever heard 

 the old birds in their natural haunts." 



It is clear that further evidence based on observation 

 under test conditions is needed. But if we may not yet 

 unreservedly accept the view that the song of birds is 

 wholly a matter of imitation, with little or no congenital 

 tendency to sing true to type, yet it is an established fact 

 that imitation is an important factor. 



If the question be now asked, — Of what service can it 

 be to the individual or the race to possess such an innate 

 tendency to imitate song, and, as Mr. Witchell contends, to 

 incorporate alien strains ? — the answer does not appear 

 to be altogether adequate or complete. According to 

 Mr. Wallace, song is primarily for purposes of recognition. 

 According to Darwin it is a means to sexual selection. 

 Since most song-birds pair, we may perhaps surmise that 

 the slight variety reached through the incorporation of 

 alien strains is a means of recognition not only specific, 

 but also individual, in its character. The hen bird, on 

 this view, not only recognizes her mate as one of her 



* P. 13, quoted in Romanes' " Mental Evolution in Animals," p. 222. 

 t Quoted in Yarrell's " British Birds," vol. i. p. 344. 



