1903
April 30
Cambridge, Mass.
Clear, calm, very warm.
  For two mornings past a Solitary Vireo has been 
singing in the Garden for about an hour after sunrise. 
Hearing him again this morning I dressed and went 
out. He was in the top of a tall elm on Sparks Street
and soon afterwards he flew into the "Jungle". I 
approached within a few paces & watched him for a 
long time. At first he sang the usual song with the
wild, clear Solitary notes including the characteristic
tus-tus. Then he changed to the song of Vireo flavifrons 
which he reproduced so perfectly that had he not been  
sitting within two or three yards of me in a good light
I would have been absolutely sure that I was listening 
to a Yellow-throated Vireo. After this he changed from
one song to the other a number of times but invariably
after a brief interval of silence. In other words his
song was never composed partly of the notes of solitarius
& partly of those of flavifrons but was either one
thing or the other during each song period of a minute
or more. Frequently after one interval of silence he resumed
the song that he had last given. He favored most that 
of his own species. Indeed there were not in all more
than there three or four song periods when he used the
notes of V. flavifrons to fifteen or twenty when he gave 
the usual Solitary notes. On the morning of the 28th I
heard him, as I know now, give the flavifrons song
once. At the time I came near concluding that I
had heard a Yellow-throated Vireo but getting the solitarius
notes distinctly a moment later I had 
been mistaken.
Solitary Vireo in the Garden sings his own song & that of V. flavifrons also.