290 A MogrH’s MUSIC. 
ing open for a number of years concerning our 
very common and familiar black-throated green 
warbler. This species, as is well known, has 
two perfectly well-defined tunes of about equal 
length, entirely distinct from each other. My 
uncertainty had been as to whether the two are 
ever used by the same individual. I had lis- 
tened a good many times, first and last, in hopes 
to settle the point, but hitherto without success. 
Now, however, a bird, while under my eye, de- 
livered both songs, and then went on to give 
further proof of his versatility by repeating one 
of them minus the final note. This abbrevia- 
tion, by the way, is not very infrequent with 
Dendreca virens ; and he has still another vari- 
ation, which I hear once in a while every sea- 
son, consisting of a grace note introduced in 
the middle of the measure, in such a connec- 
tion as to form what in musical language is de- 
nominated a turn. At my first hearing of this 
I looked upon it as the private property of the 
bird to whom I was listening, — an improve- 
ment which he had accidentally hit upon. But 
it is clearly more than that; for besides hear- 
ing it in different seasons, I have noticed it in 
places a good distance apart. Perhaps, after 
the lapse of ten thousand years, more or less, 
the whole tribe of black-throated greens will 
have adopted it; and then, when some ornithol- 
