BRITISH WAEBLBES 



it then migrates to its breeding home. Assuming that its 

 vocal powers lie dormant during the winter months, it is 

 evident that when it reaches its destination in the spring it 

 can have acquired no imitations, and therefore commences 

 the period of sexual activity with its true song plus the 

 imitative tendency undeveloped. Supposing, however, that 

 the development of this faculty occurs at an earlier stage in 

 the life of the bird than we are assuming to be the case, then 

 the imitations ought to represent not only the songs of 

 species that migrate to northern countries, but also the cries 

 and call notes of those indigenous to the African continent. 

 Now so far as an appeal to experience can be made, each 

 male upon arrival is capable of reproducing the notes of 

 other species, and, to a large extent, the imitations are of 

 the songs of the birds of the surrounding district, but 

 I cannot state definitely that any one individual to which 

 I have listened was a bird of the previous season. In all, I 

 have heard thirty-two different species copied, and no one 

 male to which I have listened has reproduced the cries of 

 more than seventeen. Of these thirty-two, no less than 

 eleven are constantly introduced into the song of the males 

 both in this country and in Holland; and of these eleven 

 again the notes of the Blue Titmouse, Swallow, Starling, 

 Linnet and Sparrow are habitually reproduced. They are 

 the more common species of the surrounding neighbour- 

 hood, we may say, and consequently would be more liable to 

 be imitated, but we must not overlook the fact that an 

 instrument capable of copying such widely divergent sounds 

 as the notes of the Blue Titmouse, Magpie, Starling and Green 

 Woodpecker, and the song of the Nightingale, is qualified to 

 imitate almost any sound to be found in bird life. How can 

 we explain this similarity in the strains reproduced ? Is there, 

 as suggested in the life of the Blackcap, an innate proclivity 

 to copy some sounds in preference to others ? Until definite 

 evidence is produced showing that the acquired imitation of 

 one generation can become the congenital variation of the 



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