INFLUENCE OF ENVIRONMENT 



199 



sounds that are heard around them. The following 

 table, for which no selection of particular singers 

 was made, indicates changes induced in the song of 

 the robin by the songs of birds which are summer 

 visitors to Great Britain. In this table the word 

 " chaffinch " denotes all the cries of the chaffinch, 

 some of which are often uttered in winter. It may 

 be as well to mention that the wood-warbler, black- 

 cap, and willow -warbler are all common summer 

 visitors to the district (Gloucestershire) where the 

 robins in question were heard. 



Here we have records of imitations of two winter 

 and early spring songsters (lark and accentor) and 

 the common chaffinch, being to some extent sup- 

 planted by those of newly-arrived warblers. These 



