vi On the Songs of Birds I 5 I 



And why should it not equally well imitate the cawing 

 of Eooks overhead, or the cooing of Wood-pigeons, 

 and any other notes of full- voiced birds to be heard 

 round about ? How is it to recognise and imitate, 

 among all these, the voice of its true parent ? 



And I might put another case of this kind, to show 

 that the difficulty is a real one. Suppose a Nightingale 

 has a nest at the roots of a tree ; when the young are 

 hatched the cock bird ceases to sing, and devotes 

 himself to feeding them. Now, there may well be a 

 Willow Warbler, a Blackcap, or a Garden Warbler 

 still in full song hard by, it may be in the very same 

 tree : why then do not the young Nightingales learn 

 the song which is thus poured into their ears all 

 day ? We might at any rate sometimes expect to 

 hear wild birds with a mixture of song, derived from 

 those of other species ; and yet, in the great majority 

 of birds at least, the song is fixed, stereotyped as it 

 were, and only alters here and there dialectically, not 

 by the reproduction of the songs of other birds. 



These are difficulties which make me hesitate to 

 accept too readily the theory that the songs are 

 acquired simply by imitation of the parent. Of 

 course if we could take a nestling from the nest 

 before he has heard the parent sing, if we could keep 

 him away from all birds' voices, and if we then found 

 that he adhered to the parental song, or, on the other 

 hand, if we found that he could not sing at all, 



