Rufous hummingbirds are small birds known for their extraordinary flight skills, flying 2,000 mi (3,200 km) during their migratory transits. Adult males have a white breast, rufous face, flanks and tail, and an iridescent orange-red throat patch or gorget. Some males have some green on back and/or crown. Females are slightly larger than males and have green, white, some iridescent orange feathers in the center of the throat, and a dark tail with white tips and a rufous base.
Rufous hummingbirds breed in western North America from southern Alaska through British Columbia and the Pacific Northwest to California. They migrate through the Rocky Mountains and nearby lowlands and may stay in one local region for the entire summer. Most winter in the Mexican state of Guerrero. Rufous hummingbirds inhabit open areas, mountainsides, forest edges, woodlands, oak forests mixed with conifers, brushy areas, and scrublands. They can also be found in flowering meadows, parks, and gardens with flowers.
Rufous hummingbirds are solitary. Both males and females are territorial; however, they defend different types of territories. The more aggressive males fight to defend areas with dense flowers, pushing females into areas with more sparsely populated flowers. Rufous hummingbirds require frequent feeding while active during the day and become torpid at night to conserve energy. They feed on nectar hovering above flowers using a long extendable tongue or catch insects on the wing. Rufous hummingbirds regularly sunbathe, fluffing out their feathers and also bathe in a cupped leaf. They sleep with fluffed feathers, retracted neck and their bill pointed upward. Rufous hummingbirds migrate during May to September to take advantage of the wildflower season. Most birds that migrate to the southeast of the United States and Caribbean Islands are juvenile birds and adult females, with adult males seldom seen.
Rufous hummingbirds are polygynous and males mate with several females during the breeding season. These birds breed in April-July. Males perform spectacular courtship displays to attract females. The female builds a nest alone in a protected location in a shrub or conifer and can be used the following year. She lays 2-3 eggs and incubates them within 12-14 days. The chicks are altricial; they are hatched helpless with gray down and eyes closed. They fledge and become independent 21 days later.
The population of the Rufous hummingbird is in decline due to its reliance on insect prey during the wintering season; it will be heavily affected by the global decline in insect populations due to pesticides and intensified agriculture. Due to climate change, many flowers that Rufous hummingbirds feed on during the breeding season have started blooming two weeks prior to the birds' arrival to their breeding locations, which may lead to Rufous hummingbirds arriving too late to feed on them.
According to the IUCN Red List, the total population size of the Rufous hummingbird is 19,000,000 mature individuals. Currently, this species is classified as Near Threatened (NT) on the IUCN Red List and its numbers today are decreasing.