Birds that live in the southern part of the US begin their return migration as early as February. Birds that live further north time their return to coincide with the flowering of their food plants. They can fly backwards and upside down and to hover. Few other birds can do any of these things, and none as successfully as the hummingbird. When a bird flaps its wing forward it creates forces called 'lift' and 'thrust', which move the bird up and forward.
Hummingbirds can rotate their wings backward, which creates downward 'lift' and backward 'thrust'.
By alternating flapping their wings forward and backward, the up and down forces and forward and back forces cancel each other out, so the hummingbird hovers in one place. It can hover long enough to suck out all the nectar it needs from a flower. It's only male hummers that have the brilliant iridescent throat feathers. They use these to display to one another. Females find it attractive, and other males are repelled.