EVOLUTION OF BIRD- SONG 



This subject seems to me sufficiently important to 

 warrant its elucidation in a separate chapter (v.), on 

 " The Simplest Songs." 



The scheme of this work is as follows : — A 

 hypothesis on the first occurrence of voice in any 

 animal is stated, and the influence of combat in 

 perpetuating it is then mentioned. The inherited 

 distress-cries of young animals (probably produced 

 long after the occurrence of the voice in adults), 

 and the retention of these cries for the purposes of 

 call-notes, lead to the consideration of the simplest 

 songs, which are mere repetitions of the call-notes, 

 and to those in which variations occur, and which 

 probably are affected by the influence of imitation. 

 The purposes of imitation are then discussed. The 

 scientific value of the notes of birds, as bearing 

 upon the ancestry of species, is considered at 

 length. 



By " bird-song " I mean the whole range of the 

 voice in birds. Songs I have defined as vocal 

 utterances, not being alarm-cries or call-notes.^ 



The word " phrase " (as I have employed it in 

 this work) does not mean a strain in music, but a 

 period of song ; so that, if a bird sang a few notes 

 at one time, then paused and sang them again, and 



1 Zoologist, July 1890. 



