1 1 6 E VOL UTION OF BIRD-SONG 



severe weather in autumn and winter. The red- 

 wing has a single alarm-cry exactly like one 

 of the blackbird, which is absent in fieldfare, thrush, 

 and mistle-thrush, but occurs in the American 

 robin. 



The young redstart and young robin have at 

 one period (just after leaving the nest) the same 

 cries. In the redstart and nightingale we find a 

 cry not uttered by blackbird, American robin, mistle- 

 thrush, thrush, or robin, except as an imitation. It 

 is the little whistle 



. 8ve. 



This is an alarm -cry of redstart, nightingale, chiff- 

 chaff, and willow-warbler, being especially prominent 

 in the three last ; and it is uttered in a modified 

 tone and at a lower pitch as an alarm by the 

 whitethroat. In the young willow-warbler the cry 

 is usually heard as a whistle on the first of the two 

 notes here indicated ; but upon the excitement of 

 fear the final note is added. The alarm-croak 

 of the nightingale seems to be slightly modified in 

 the lesser whitethroat and sedge-warbler. 



There are considerable points of resemblance 

 between the songs of several of the thrushes and 

 the warblers, which I have discussed, and these 



