BLACKCAP 



parts of the song of the Nightingale and the Garden- Warbler, 

 amongst other species, being introduced. Now these males 

 would not have left the nest until the middle of the previous 

 June, and at this date both the Nightingales and Garden- 

 Warblers are silent; one may, perhaps, hear occasionally a 

 momentary outburst of song from a Nightingale, or a short and 

 quiet warble from a Garden- Warbler, but even this soon ceases, 

 and neither of these species then sing again before leaving this 

 country. These males next return at the beginning of the 

 following April, while the Garden-Warblers do not arrive until 

 some weeks after this date, and the Nightingales about the 

 same time, but they are generally rather later. It is, there- 

 fore, clear that they could not have acquired these imitations 

 during the few weeks that they have been in contact with 

 these other species in this country. But there remains the 

 period between September and the following April, the time 

 in which they are resident in their winter home. What 

 happens during these months ? My impression has always 

 been that such species as the Nightingale and Garden- Warbler 

 do not sing. If I am wrong in thus thinking, it is clear that 

 they would have had ample opportunity of acquiring them 

 during this period ; on the other hand, if I am right, and 

 these species, so far as their song is concerned, are silent, 

 then we can only regard the imitations as congenital. 



There are other points in connection with the imitative 

 faculty which are difficult to explain except on the hypothesis 

 of transmission. Why, for instance, in almost every series of 

 imitations, should the song of the Nightingale and Garden- 

 Warbler be introduced ? It is true that the males have 

 considerable opportunities of hearing them, but it is also true 

 that there are other species inhabiting the same situations 

 which are more frequent and more persistent singers. Or, how 

 is it that the series of imitative strains is to so large an extent 

 composed of the songs and call-notes of our indigenous 

 species ? As far as the song of our own migrants, in their 

 winter home, is concerned, silence may reign, but the males 



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