By Ron Divelbiss
All birds can fly forward, and some birds can hover for a short spell, but only hummingbirds can zip into backward flight, too. This is possible because their wings actually flip over on each stroke when hovering or going backward, so that the leading edge, which remains facing front in other birds, works in either direction. Hummingbirds also work their wings from what would be our shoulder joint, instead of flapping them at the elbow and wrist joints like other birds. To really appreciate the fantastic mechanics of a hummingbird's wings, try it yourself.
- Hold your arms out with thumbs forward so your arms are slightly ahead of your shoulders.
- Now swing your arms so that they point backwards, while rotating your arms at the shoulders so that your thumbs face back.
- Repeat, so that thumbs again are facing front as you rotate your arms and bring them forward.
- Now do it 70 times a second.
Hey, you're a hummingbird!