VA RIA TION IN BIRD- VOICES 1 5 3 



(in //#.). I have often noticed that individual 

 nightingales differ in the frequency with which they 

 commence their phrases with the little upwardly- 

 slurred whistle, which is one of their call -notes. 

 Speaking very generally, but from much observa- 

 tion, I should say that in Gloucestershire the call 

 is on an average uttered at the beginning of one in 

 every four phrases of the nightingale. I have heard 

 a willow-warbler (on loth June) interrupt his usual 

 mellow phrase with a sibilous repetition, like the 

 song of the wood-warbler, but less prolonged. 



Early in July, a male house-sparrow, which appar- 

 ently lived near my bedroom, acquired a new note : 

 it was seemingly a shout, and resembled the very 

 rapid upwardly -slurred whistle, sounding like the 

 word " twit," so frequently uttered in early spring 

 by the male chaffinch (p. 43, ante). The sparrow 

 repeated this cry every morning with the greatest 

 persistence, and his manner of looking about 

 during the performance indicated some pride in 

 it. After ten days or so had elapsed he seemed 

 to tire of the cry, and he gradually abandoned it. 

 I never heard another house -sparrow utter this 

 note. A neighbour also called my attention to 

 the cry, which he thought to proceed from some 

 uncommon bird. In June 1891 I heard at 



