EVOLUTION OF BIRD-SONG 



this species : " Their cry resembles the words chica> 

 chica, chica, repeated four or five times in succes- 

 sion, and ending with a shorter syllable, chike? In 

 Gloucestershire the principal spring call -note is a 

 rapidly downward-slurred whistle, sometimes followed 

 by the quick repetition of a harsh cry, the whole 

 sounding something like this (the actual pitch is 

 wholly immaterial) : 



Cheeu sa sa sa Cheeu Cheeu Cheeu sa sa sa sa. 



This seems to me the only characteristic call-note of 

 the marsh titmouse. The well-known cry fink or 

 pink of the chaffinch has often been termed the 

 call -note of the bird, and even Yarrell has made 

 this mistake. My experience convinces me that 

 the cry is not a call -note. The chaffinch has several 

 notes which are of this character : one is a soft cry 

 almost exactly like the ordinary chissick of the 

 house -sparrow, and is uttered by both sexes at 

 the breeding season ; this also is the call-note by 

 which the young attract their parents. Another 

 cry which I have often heard uttered by male 

 chaffinches before the breeding season is a loud 

 short whistle very rapidly slurred upwards, in the 



