The ruby-throated hummingbird is 2.8 to 3.5 inches long with a 3.1- to 4.3-inch wingspan at maturity, and females are larger than males. The birds are metallic green in color with grayish-white undersides and black wings. Only males have red throat patches.
The ruby-throated hummingbird is the only hummingbird that breeds in eastern North America. A male establishes a territory and courts females that enter it by flying, diving and showing his red plumage. Females build nests in shrubs or trees and lay one to three eggs that they incubate for two weeks. They then care for the young birds for three weeks by feeding them insects for protein.
The hummingbirds spend winters in Mexico and Central America as far south as Panama. Some birds make the 900-mile journey non-stop across the Gulf of Mexico and may double their body weights before the journey.
The ruby-throated hummingbird's habitat includes open woods, clearings, city parks and gardens in the summer and dry tropical scrub in the winter. These birds do not typically live in rain forests. Their diet consists of nectar from flowers, and the birds eat by hovering over the flowers while beating their wings up to 53 times per second. Their feeding process pollinates the plants.