The family Trochilidae includes 23 species found in North America.

Hummingbirds include the smallest living birds with most species 6-13 cm long and 2-9 gms in weight. The bill is long (6-110 mm), slender, tubular, straight or curved. The tongue is long and adapted for nectar-feeding. Wings are adapted for hovering forward and backward. Hummingbird's high metabolism required for hovering is reflected in relatively large heart and lungs and high concentration of red blood cells. The plumage is usually iridescent.

All hummingbirds feed on nectar supplemented with insects and spiders. Different species utilize different kinds of flowers and extract nectar in different ways, hence the variation in the shapes and sizes of bills. Many plants are pollinated by hummingbirds which pick up pollen on the head plumage while feeding. Most species insert the bill into the corolla of a flower to obtain the nectar. A few puncture the the base of the corolla tube to gain access to the nectar. Hummingbirds have been observed taking juice from ripe fruit and some North American species take sap from openings in the bark of trees made by sapsuckers. Insects are taken on the wing or gleaned from foliage. Spiders are taken from foliage or webs. When food is scarce, or during extremely cold weather, hummingbirds may become torpid and appear to be dead, but will revive when warmed.

Sexual dimorphism tends to be highly developed in species in which solitary males display in a defended territory to which the females come for mating. Each male defends several song perches and mating occurs on these perches. In most species the males are polygamous and the females build the nest, incubate the eggs and rear the young alone. 

In most species the nest is a small, compact open cup placed astride a branch and composed of vegetable down, fibers and sometimes moss, bound together and to the branch with cobwebs. In some species lichens are attached to the outer surface. The clutch is always two white, elliptical eggs. Larger clutches indicate that more than one female has laid in the nest. Incubation begins after the second egg is laid and ranges from 14-19 days. The young are covered with sparse down and are brooded frequently for the first 8-12 days, after which brooding ceases. Small nestlings defecate in the nest and the female removes the droppings; older nestlings defecate over the rim of the nest. The female feeds the young on insects and spiders by regurgitation from her crop directly into the crops of the nestlings by inserting her bill into their throats. Fledging varies from 18-28 days and is influenced by weather. The female continues to feed the fledged young for up to about 40 days.