i84 EVOLUTION OF BIRD- SONG 



hedge-sparrow, blackbird, and blackcap, which sing 

 mellow tones and intervals of pitch rather than 

 imitations of other sounds, may have acquired this 

 music partly through the influence of the murmurs 

 and gurgles of rippling streams. Most of us have 

 observed the musical sounds caused by small jets of 

 water falling or dripping into water-butts, and some 

 may have noticed the similarly pleasing sounds 

 occasionally repeated almost incessantly and without 

 variation by tiny waterfalls in a streamlet. Having 

 often observed this " music of streams," as it may be 

 called, I one day set down in musical notation as 

 much as possible of the music of a babbling stream. 

 Of course the intervals written could only be con- 

 sidered as representing approximately the sounds 

 produced. Much of this music was far too intricate 

 and vague to follow, and it was only by close 

 attention that I could work out the following 

 examples, which labour was greatly simplified by the 

 continual repetition of the same strains, as commonly 

 occurs. The first was very distinct, and ran thus : 



There was a great accent on the note which I have 

 placed first in the bar. Some twenty yards off 



