Song Birds and Water Fowl 
as compared with other songs, but in their per- 
fect ease of imitation, in which they are unri- 
valled. ‘This is due to their having what the 
scientist calls the basal element of all musical 
sound—fixed intonation, definite pitch, pro- 
duced by extreme rapidity and equidistance of 
successive sound - waves —that basal element 
that runs through the entire gamut of musical 
tone, from its grossest to its most spiritual mani- 
festation, from the depths of a buzz-saw to the 
heights of a Jenny Lind. 
The difficulty, usually amounting to an im- 
possibility, of reproducing bird-songs is partly 
due to great intricacy or confusion of rhythm, 
as in any genuine warble, like that of the 
warbling vireo and wren ; partly due, also, to 
that surprising and inimitable change of tone- 
color that passes suddenly over the successive 
phrases of many a song, and even over the sev- 
eral notes of the same phrase ; as in the case of 
the wood thrush, one of whose phrases seems 
like a flood of golden light, and the next like a 
stream of sparkling water ; but perhaps the great- 
est difficulty of all, in reproducing a song, is in 
the almost incessant conversational slide of the 
voice—a sort of slippery pitch—instead of the 
definiteness of strictly musical tones, and in the 
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