You've probably seen hummingbirds hover in mid air. Most birds flap their wings up and down, but hummingbirds move their wings in a figure-eight pattern.
With each flap they twist their wings one-hundred-eighty degrees so that they create a downward thrust on both the forward and backward strokes.
If each loop of the wings is of the same strength, they hover. They can go forward, backwards, or sideways by tilting their wings in the direction they want to go, much like a helicopter.
In order to hover, hummingbirds have to be really strong. Their wing muscles are thirty percent of their total weight. When a small hummingbird hovers it flaps its wings about eighty times per second.
Hummingbirds have to eat close to fifty percent of their weight in food everyday to keep up their strength. They eat things that are packed with calories and produce lots of reusable energy, like seeds, nuts, nectar, and fruit.