Note this is not technically a robot, it’s more accurately an automaton. I made it as an experiment to test the capabilities of my new 3D printer.
The mechanism was downloaded from Thingiverse: Hummingbird by gzumwalt. The music in the video is “The Birdwatcher” by Vulfpeck. All parts were printed in PLA. Critical strength parts like shafts, screws, wheel body, etc. were printed at 100% infill. I reprinted several of the 30 tooth spur gears at about 95% scale to make them rotate more freely. Several of the parts required extensive sanding and fitting to make it move smoothly.
Autodesk Fusion 360. The original base slides right into the sub-base. Files available here. The only other parts needed are a small toggle switch and a 4 cell AA battery holder (i used Jameco #105858).