Hummingbirds, members of the family Trochilidae, are some of the smallest birds in the world.

They live in the Americas.

Many hummingbird species in Canada and the United States migrate and spend the winter in Mexico or Central America. Some ruby-throated hummingbirds migrate all the way from Canada to Panama.

The bee hummingbird is the smallest bird on Earth. Also known as the zunzuncito, the bee hummingbird is native to Cuba and Isla de la Juventud. It is about 5 centimeters (2 inches) long and weighs about 1.8 grams (about 6 hundredths of an ounce.)

Booted racket-tail hummingbirdHummingbirds are well known for their unique flying abilities. They are the only birds that can fly backwards.

They can also hover in one spot. In order to hover, hummingbirds must move their wings in a figure 8 motion.

Sunbirds also have the ability to hover.

Hummingbirds can fly very quickly. Normally, hummingbirds fly at about 25 miles per hour.

During courtship displays, males perform dives in which they can reach speeds greater than 60 miles per hour.

To attain such speeds, a hummingbird must beat its wings so rapidly that it makes a humming noise -  That is where the name "hummingbird" comes from.

Ruby throated hummingbirdA hummingbird may beat its wings 80 times in a second.

Hummingbirds eat mostly nectar. Their diet also includes insects and spiders, which they eat to obtain protein.

They collect nectar in grooves in the side of their tongues.

Hummingbirds have extremely high metabolisms. Insects are the only animals with higher metabolisms.

The heart rate of a hummingbird can reach 1,260 beats per minute.

To maintain its high metabolic rate, a hummingbird must consume at least its own weight in nectar every day.

A hummingbird enters a state of torpor, in which its metabolism slows down dramatically, at night and whenever it cannot easily obtain food. During torpor, the hummingbird's heart rate may drop down to between 50 and 180 beats per minute.

Hummingbirds have small, weak legs and feet, and fly, rather than walk, to get from place to place. Swifts and hummingbirds together make up the order Apodiformes, whose name is Greek for "without feet." Although these birds do have feet, their feet can be used for little more than perching.

Hummingbirds are extremely territorial.