BLACKCAP 



facts, and the analogy of the deterioration of the colour and 

 plumage as a result of the same cause, and that the develop- 

 ment of the vocal powers in the spring corresponds with that 

 of the sexual organs, showing how intimately associated the 

 one is with the other ; bearing all this in mind, we can with 

 some confidence say that the deterioration, such as we find, 

 is the very result that we should under the conditions 

 anticipate. 



(3) Imitation forms a large part of the vocal efforts of the 

 males, and in this respect I have been able to detect little 

 difference between immature and adult birds. In both cases 

 the imitations are very perfect and unmistakable. Many of 

 them are the immediate copies of sounds produced by mem- 

 bers of other species ; for instance, when a Blackbird utters 

 its alarm-note, a male will sometimes at once repeat it note 

 for note, or when some other species not far distant, such as 

 a Eedstart (Buticilla phoenicurus), happens to sing, he will 

 pause in his song and then reproduce a repetition of the 

 sound. This demonstrates how acute their sense of hearing- 

 is. But the greater part of this imitation is produced from 

 memory, as is amply shown by the song of the males 

 early in the spring before the species imitated have arrived. 

 Those most frequently copied are the Nightingale and Grarden- 

 Warbler, but I have heard in addition to those already 

 mentioned, imitations of the Whitethroat, Sedge- Warbler, 

 Starling (Sturnus vulgaris), Thrush (Turdus musicus), Linnet 

 (Acanthis cannabina), Great Titmouse (Parus major), Long- 

 tailed Titmouse (Acredula caudata), Missel-Thrush (Turdus 

 viscivorus), and Tree- Creeper (Gerthia familiaris). 



The sequence of imitative strains does not appear to be 

 always similar in the same individual ; the various imitations 

 being utilised anyhow, the same one is often repeated, and 

 some are made use of much more frequently than others. 

 When, upon further investigation, we attempt to find a solu- 

 tion of the method by which these imitations have reached the 



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