Hummingbirds (family Trochilidae) are small birds capable of hovering in mid-air due to the rapid flapping of its wings (15 to 80 beats per second, depending on the size of the bird). They are the only bird that can fly backwards. They are named for the characteristic hum of their rapid wing motion, and are attracted to many flowering plants such as shrimp plants. Hummingbirds feed on the nectar of these plants. They are important pollinators, especially of deep throated flowers. They are especially attracted to red flowers: hummingbirds can be attracted by feeders stocked with sugar water. Many species will also eat insects. Male hummingbirds are usually brightly coloured, females duller. The males take no part in nesting. The nest is usually a neat cup in a tree. Two white eggs are laid, which are large compared to the bird. Incubation is typically 14-19 days. The Bee Hummingbird is, at 1.8 grams, the smallest bird in the world. A typical North American hummingbird, the Ruby-throated Hummingbird weighs approximately 3 grams, length 7.6 cm (3 in).
There are between 325-340 species of hummingbird, depending on taxonomic viewpoint, divided into two subfamilies, the 34 hermit species and the typical hummingbirds which includes all the others.
Hummingbirds are thought to have evolved in South America, and the great majority of the species are found there. All the most familiar North American species are thought to be of relatively recent origin.