The World's Smallest Bird The smallest hummingbirds are no bigger than bees. The'mum' comes from their wings, which move 70 times a second. Hummingbirds can fly at top speeds of 80 kilometers per hour. They can stay still in the air like a helicopter, and they can even my backwards. A species of hummingbird lays the tiniest bird eggs, about the size of a fingernail.