Hummingbirds include the smallest birds in the world, but they belong to one of the largest group of birds, the Trochilidae family. These enchanting birds are found in deserts, mountains, and plains, but most live in tropical rain forests. Their name refers to the humming sound made by their tiny, beating wings; each species creates a different humming sound, depending on the speed of its wing beats. In the Caribbean, people call the hummingbird el zunzun. These energetic dynamos have been around for ages; hummingbird fossils found in Germany are said to be more than 30 million years old.