1910
May 25
(No 2)
[May 25, 1910]
dozen times or more his gorget expanded and glowing like
a burning coal or a big ruby. Standing within two yards of
the bush (which he just brushed at each downward swing) I 
distinctly heard him make three different sounds at once.
One was the shrill squeaking made at all seasons, by
both sexes, when disturbed or excited, another the loud
bee-like droning sound of wings (sometimes varied to
a sharp buzzing rather than a droning sound), the third
a humming-top sound very much like that made by Trochilus
platycercus as I heard it in Colorado years ago. The 
squeaking and buzzing were incessant or nearly so; the
humming top sound was emitted most of the time when
the bird was rising & falling but it ceased for an 
instant when he was poising. I have never heard 
T. colubris make it before perhaps because I have never been
near enough to a plunging [male]. The mystery is how could the
bird make this sound & the humming or droning one at the same
time. That he did it is beyond all question.