Selasphorus sasin
Allen's hummingbird
(Also: Allen's hummingbird)

Allen's Hummingbird, Selasphorus sasin, is a migratory bird which summers along the pacific coast of the United States from Oregon to southern California. During the winter it migrates to northwestern Mexico.

(Peterson 1990, Terres 1980)

The Allen's Hummingbirds can be found in bushy woods, gardens, flower filled mountain meadows, and parks.

(Cassidy 1990, Stokes 1996)

Allen's Hummingbirds are among the smallest birds, they are only 7.5 to 9 cm (3-3.5 in.) long and typically weigh a little over 3 grams (0.1 oz.). In appearance they resemble their closest relative, the Rufous Hummingbird. A male Allen's hummingbird has a fiery red-orange throat, white collar, and metallic green on its back and cap. The female's upper body is green. The tail and sides are orange-brown and the throat and central belly is white with iridescent dots on its throat.

(Stokes 1996, Farrand 1988, Terres 1980)

Individual male and female Allen's Hummingbirds defend separate feeding territories. During the breeding season, which typically begins in February the Female hummingbirds begin to visit male territories. At first a male might be aggressive towards her, but then he will do aerial displays. The male uses a J-shaped flight as a signal. He will fly up about 23 m (75 ft.) and come down and up about 7 m (25 ft.) He will then fly in a back-and-forth flight that resembles a giant pendulum. At the peak of the arc he will make a prolonged buzz. The female hummingbird then leads him closer to her feeding territory to begin copulation, mating lasts about 3-5 seconds, and then the male returns to his territory.

When the Allen's Hummingbird is not feeding during the night its body goes into a state of torpor. It lets body heat escape and its heart rate drops dramatically. It clings to a branch and sits almost life-less to conserve energy. At sunrise its body temperature starts going up again and it is ready to start feeding.

Most hummingbirds including the Allen's Hummingbird are not social animals. Since they spend most of their time feeding on nectar, they are better off feeding alone. Each bird claims its territory in which to feed and they become very aggressive birds if there are any trespassers. The male hummingbird will use its aerial flights and intimidation displays to chase away predators and trespassers.

(Cassidy 1990, Stokes 1989, Arizona-Sonora Desert Museum 1998)

Allen's Hummingbird has a long narrow bill and long tongue. This feature allows it to obtain nectar from flowers. They feed every ten to fifteen minutes and visit approximately 1,000 flowers a day. Nectar is their main source of energy, but they also obtain protein from small insects like flies, ants, small beetles, tiny wasps, and other small insects. Because the hovering flight used by these birds to gather nectar requires phenomenal amounts of energy, the Allen's hummingbird has to consume over twice its weight of nectar each day.

(Cassidy 1990, Arizona-Sonora Desert Museum 1998, Stokes 1989)

There is neither positive nor negative economic importance for the Allen's Hummingbird, but they do help in the pollination of flowers.

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Prolonged hovering and flying backwards are unique to hummingbirds. This amazing flight ability requires huge amount of food (caloric input) in order to sustain the flights. This is why hummingbirds have to constantly be feeding during the day and go torpid at night. If a human used energy at the rate that a hummingbird does, he/she would have to consume about four hundred pounds of potatoes and a thousand quarter-pound hamburgers every day.

(Arizona-Sonora Desert Museum 1998)