- Hummingbirds are birds native to the Americas.
- Hummingbirds measures 7.5–13 cm (3–5 in) in length.
- The smallest extant hummingbird species is the 5 cm (2.0 in) bee hummingbird, which weighs less than 2.0 g (0.07 oz).
- The largest hummingbird species is the 23 cm (9.1 in) giant hummingbird, weighing 18–24 grams (0.63–0.85 oz).
- Hummingbirds split from their sister group, the swifts and treeswifts, around 42 million years ago (Mya).
- The common ancestor of extant hummingbirds is estimated to have lived 22 Mya in South America.
- They are known as hummingbirds because of the humming sound created by their beating wings, which flap at high frequencies audible to humans.
- The wing-flapping rates, vary from around 12 beats per second in the largest species to around 80 per second in small hummingbirds.