HEREDITY 99 



redstart to the true warblers. Whether or not the 

 snapping note of the redstart resembles the short 

 note, tac tac, of the blue-throated warbler (Ruticilla 

 suecica, Linn.) (Bechstein, Cage Birds, p. 235), 

 or the "short snapping note of the latter" (ist ed. 

 Yarrell, vol. i. p. 236), I cannot say ; but I know 

 that the tack alarm of the blackcap is not unlike 

 the cJiick alarm of the redstart. Yarrell observed 

 that when bluethroats are alarmed by any one 

 approaching their nest, their notes of alarm or anger 

 resemble those of the nightingale. He also noticed 

 that the bird very frequently jerks up its tail in the 

 manner of the robin and nightingale (ibid.). The 

 tack of the blackcap was wrongly termed by 

 Bechstein a call-note : it is only so much of a call- 

 note as an alarm may be. 



In all the above instances (except perhaps in 

 that of the bluethroat) the rattling alarm or the 

 chick or tack are alarm-cries, and they blend in 

 small degrees one from the other. The common 

 spotted flycatcher utters after its young are hatched, 

 and not often before, a short alarm, chick, which 

 then often succeeds the ordinary call-squeak of the 

 bird. This chick is practically the same note as 

 that of the redstart, and the preceding squeak is 

 precisely like the call-squeak of the young robin 



