Selasphorus rufus (J.F.Gmelin, 1788)

Nomenclature

This species is scientifically named Selasphorus rufus (J.F.Gmelin, 1788), commonly known as the rufous hummingbird.

Adult Male Plumage

Adult males have a white breast, rufous face, flanks and tail, and an iridescent orange-red throat patch called a gorget. Some males have green markings on their back, crown, or both.

Female Plumage

Females have green upperparts, white underparts, some iridescent orange feathers in the center of the throat, and a dark tail with white tips and a rufous base. Females are slightly larger than males.

Species Identification Challenges

Females and rare green-backed males of this species are hard to tell apart from Allen's hummingbird. The characteristic notched shape of the second rectrix (R2) is an important field mark to distinguish adult male rufous hummingbirds from adult male Allen's hummingbirds.

Size and Measurements

This is a typical small hummingbird, weighing 2–5 g (1⁄16–3⁄16 oz), measuring 7–9 cm (3–3+1⁄2 in) long, with a wingspan of 11 cm (4+1⁄2 in).

Western Migration Pattern

For distribution and habitat, western rufous hummingbirds migrate through the Rocky Mountains and nearby lowlands from May to September to exploit the wildflower season.

Summer Feeding Territoriality

Some individuals remain in one local area for the entire summer; in this case, migrants, like breeding birds, often aggressively take over and defend feeding sites.

Winter Range and Migration Distance

Most individuals spend the winter in wooded areas of the Mexican state of Guerrero, traveling over 3,200 km (2,000 mi) overland from their nearest summer range — an exceptional journey for a bird that weighs only 3 to 4 g (3⁄32 to 5⁄32 oz).

Migration Timing

Adult male rufous hummingbirds usually migrate slightly earlier than females or young birds.

Eastern Migration Classification

Because juveniles and females of this species are nearly impossible to tell apart from Allen's hummingbird without close inspection, eastern rufous migrants are often classified as "rufous/Allen's hummingbirds".

Feeding Habits

For feeding, rufous hummingbirds feed on flower nectar with a long extendable tongue, and also catch flying insects while on the wing.

Energy Conservation

They need to feed frequently when active during the day, and enter torpor at night to conserve energy.

Predation Risk

Due to their small size, they are vulnerable to predation by insect-eating birds and other animals.