( Trochilus Platycercus ) 
by the Broad-tailed. Humming-bird ~~J as" I heard it in 
Colorado years ago. The squeaking and burr-i4g were incessant 
or nearly so; the humming-top sound was emitted most of 
the time when the bird was rising and falling but it ceased 
for an instant when he was poising. I have nerer heard 
a Ruby-throated Hummingbird (Trochilus 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 and the humming or droning one at the same time. That 
he did it is beyond all question. 
