The rufous hummingbird (Selasphorus rufus) is a small hummingbird, about long with a long, straight and slender bill. These birds are known for their extraordinary flight skills, flying during their migratory transits. It is one of nine species in the genus Selasphorus.
Taxonomy
The rufous hummingbird was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with all the other hummingbirds in the genus Trochilus. He coined the binomial name Trochilus rufus. Gmelin based his description on the ruff-necked hummingbird described by John Latham in 1782 and the ruffed honeysucker described by Thomas Pennant in 1785.
The type locality given by Gmelin was Nootka Sound on the west coast of Vancouver Island in western Canada. However, breeding was estimated to occur in northwestern North America and wintering in westcentral Mexico. The rufous hummingbird is now placed with eight other species in the genus Selasphorus that was introduced in 1832 by the English naturalist William Swainson. The genus name combines the Ancient Greek selas meaning "light" or "flame" with -phoros meaning "-carrying". The specific epithet rufus is the Latin word for "red". The species is considered as monotypic: no subspecies are recognized. This is a typical-sized hummingbird, being a small bird. It weighs , measures long and spans across the wings.
Distribution and habitat
thumb|right|Perched female
Western rufous hummingbirds migrate through the Rocky Mountains and nearby lowlands from May to September to take advantage of the wildflower season. They may stay in one local region for the entire summer, in which case the migrants (like breeding birds) often aggressively take over and defend feeding locations. Most individuals winter in wooded areas in the Mexican state of Guerrero, traveling over by an overland route from their nearest summer home – a prodigious journey for a bird weighing only .
Adult male rufous hummingbirds tend to migrate slightly earlier than females or young. Since juveniles and females are essentially indistinguishable from Allen's hummingbird, unless confirmed by close inspection, eastern rufous migrants may be classified as "rufous/Allen's hummingbirds". When hovering during fasting, rufous hummingbirds oxidize fatty acids to support metabolism and food energy requirements, but can rapidly switch to carbohydrate metabolism (within 40 minutes) after feeding on flower nectar.
left|thumb|A juvenile male nectaring on [[Cleome serrulata|Rocky Mountain beeplant in Wyoming]]
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. Females on the other hand are not given access to the high concentration food sources, because the males fight them off. Due to climate change, many flowers that the rufous hummingbird feeds 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.