It's all too brief, but check out the lovely motion of this wooden mechanical bird. The bird is set in motion by pulling a string below (not shown). The YouTube description says it was made by Hans Happ (1899-1992), a German painter and creator of mechanical art toys.
Here is a beautifully made flying bird mobile made by Kenji Hayami. The sculpture depicts a white crane with a red crest in flight. The piece uses nice woods, an adjustable counter-balance system, and clever magnetic hinges. I wish I could see it in motion. I bet it is beautiful.
Here is the page with more info on the white crane wooden bird mobile.