Hummingbirds are the smallest of all birds.

Tiniest of the 19 species in the United States is the calliope hummingbird, which is about 3 inches long and weighs only a few grams.Hummingbirds are brightly colored, and feed on small insects and nectar from flowers. They fly quickly, darting upward, downward, backward or forward. They can also hover motionless.