Most birds get all the lift they need to fly with the downward stroke of their wings—meaning there’s no upward force being produced as they raise them back up. Hummingbirds, on the other hand, produce lift with both their upward and downward wing strokes, creating air vortices that the tiny birds use to fly with incredible maneuverability.
For a recent article delving into the science of what makes hummingbirds so agile, National Geographic collected a series of incredible high-speed videos of the birds in flight. Watching a hummingbird expertly navigate the tumultuous currents of what looks like a major hurricane is no less impressive when it’s revealed that the bird is actually flying in a small, controlled wind tunnel.
http://video.nationalgeographic.com/video/magazine/170706-hummingbirds-anand-varma-slow-motion
source: gizmodo.com by Andrew Liszewski