io8 



EVOLUTION OF BIRD-SONG 



the repeated musical phrases of the former bird 

 generally consist of from three to five notes, those 

 repeated by the latter are generally of only two, or 

 sometimes three notes. The following transcripts of 

 the notes sung by two " robins " {i.e. thrushes) near 

 my rooms at Vancouver will convey a good idea of 

 the monotonous character of the performances of this 

 species. The strains are marked by double bars ; 

 and each was repeated from six to a dozen times 

 before the bird attempted a variation. (The pitch is 

 not material.) 



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-1^ — ^ 



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Though the British blackbird never sings in this 

 barbarous fashion, it may be sometimes heard to 

 repeat the same strain several times in succession ; 

 and this most often occurs in birds still wearing the 

 infantile flight-feathers, which are shed at the second 

 moult. (See also page 144, /^j-/.) 



The song of the ring- ousel (which, however, I 

 have only heard on one occasion) appears to be 

 intermediate between those of the mistle-thrush and 



