198 EVOLUTION OF BIRD- SONG 



winter, and spring ; and during these seasons the 

 voices of the great and blue titmice are very 

 noticeable. In gloomy dells about the wooded 

 hills the coal-tit is very common ; and here young 

 robins are to be found during summer and early 

 autumn at which period, as we know, they are 

 receiving strong impressions of sounds. The hedge- 

 accentor and blackcap are very common, especially 

 in the haunts of the robin. In the open fields we 

 find buntings numerous, and during summer the 

 swallow's voice is heard almost as often as theirs ; 

 while in every sheltered valley, and up the hillsides, 

 the tree -pipit pours out his music. The peewit 

 frequents the open fields throughout the year, but 

 in small numbers. Greenfinches are abundant. 

 Every evening the partridge's call may be heard 

 in the fields. The jackdaw is plentiful, and is 

 often associated with rooks and starlings. The 

 chaffinch is abundant, as are also the commoner wag- 

 tails in their seasons. 



Thus we find that each of the five imitative 

 species above mentioned has preferred to reproduce 

 the cries of birds which are abundant, or whose 

 voices are especially noticeable, in its neighbourhood. 



Song-birds which are imitative are not unnatur- 

 ally influenced by changes in the more persistent 



