You've seen hummingbirds hovering, whether they stand still in the air as they somewhat superciliously look you over or as they sip nectar from flowers. You might well wonder how they do that after all, they don't have rotors like a helicopter or seemingly much of anything except the blurs made by their wings. What was going on had to wait on the invention of high speed photography. A series of pictures was taken extremely rapidly and then played back at a normal speed slow motion magic.
And what did this slowed-down action show? Enough to make your
shoulders really sore. At each up and down cycle, the wings essentially are turned from
top surface down to bottom surface down, giving lift on both the upstroke and the
downstroke. Try this with your arms, palm of hand up, swung over your head and behind
you; then swing your arms forward over your head and downward, turning the palms of
your hands toward the ground as you do so. Now, to get the full effect, do this 80
times a second.
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.
Mildred E. Mathias Botanical Garden, UCLA.