EVOLUTION OF BIRD- SONG 



note of the redwing is described by Dr. A. G. 

 Butler zsphee-ur, the call-note of the North American 

 bluebird, a distant connection of our thrushes ; 

 " which note," he writes, " I have also heard uttered 

 exactly in the same way by the redwing " (in litt.}. 

 Curiously enough, the cry employed by the tree- 

 pipit when migrating is not unlike that of the 

 redwing ; in fact, it has just the same tone, but is 

 shorter and less loud. The same cry in the meadow- 

 pipit is yet more brief. 



The blackbird, when suspicious of danger, utters 

 at intervals of a few seconds a short full note, 

 sounding like the word quilp. This is especially the 

 case in autumn and winter. The note, as I have 

 stated, is often raised in pitch, and the rapidity and 

 continuance of its repetition are often increased until 

 the common rattling alarm of the species is produced. 

 But the redwing thrush, when suspicious of danger 

 (at least in winter), utters the quilp as an alarm in 

 precisely the same manner and tone as the blackbird. 

 This I have many times observed ; but I have never 

 heard the redwing make any attempt to repeat the 

 sound rapidly, or in varied pitch, in the manner of its 

 near relation, the blackbird. The American robin 

 has the same note of suspicion. The cries of the 

 nestling young of both blackbird and thrush are 



