Chickadee Heart . 12" x 12" . turkey feather
When a bird flaps its wing downward, feathers push on the air to keep a bird aloft, right? Then what happens when the bird moves its wing back up? Wouldn’t feathers push the air going the other way forcing the bird down? It would except for several things happening at the same time with the wings and feathers. Here are some:
1. The wing twists upward on the up-beat
2. The big flight feathers on the wing tips angle up so they aren’t flat against one another but are open like a louvered window shade that when opened you can see out
3. Each feather lets a little bit of air pass through; a little more on the leading edge letting more air than the trailing edge. This is part of what allows feathers to separate from each other on the upbeat and helps them stick together on the downbeat. (Air Transmissivity of Feathers, Muller and Patone, 1998)