Allen's Hummingbird (Selasphorus sasin) is a common hummingbird that breeds in coastal California and southwestern Oregon (U.S.A.) and winters mainly in Mexico, although it is found casually in winter along the Gulf Coast of the southeastern United States. The population on California's Channel Islands and the nearby mainland is nonmigratory. This is one of the two common nesting hummingbirds in northern California gardens (the other being Anna's Hummingbird, Calypte anna). This species is closely related to the Rufous Hummingbird (Selasphorus rufus), its more northern and more broadly distributed counterpart. Females and immatures of these two species are nearly impossible to distinguish in the field, but adult males can usually be distinguished by back color (typically solid green in Allen's and mostly rufous in Rufous).
Breeding Allen's Hummingbirds are found in wooded or brushy canyons, parks, gardens, and mountain meadows. In general, this species seems to have adapted fairly well to moderately developed residential areas. In their wintering range in Mexico, Allen's Hummingbirds are found mainly in foothill and mountain forests. They frequently feed at red tubular flowers. The nest site is typically on a horizontal or diagonal branch in a tree or shrub, generally low but sometimes up to 27 m above the ground. The nest, built by the female alone, is a neatly constructed cup of moss and plant fibers held together with pieces of spider web and lined with fine plant down, The outside is camouflaged with pieces of lichen. Old nests may be repaired and re-used. The clutch of two white eggs is incubated by the female alone for 17 to 22 days; the female is also solely responsible for feeding the young after hatching.The nest reportedly stretches as the young birds grow. Age at first flight is around 22 to 25 days.
Male Allen's Hummingbirds exhibit a J-shaped courtship display flight: flying high, diving steeply with a metallic whine at the bottom of the dive, then curving up to hover at moderate height. This is often preceded by a back-and-forth pendulum-like flight in front of the female.
(Kaufman 1996; AOU 1998)
- American Ornithologists' Union. 1998. Check-list of North American Birds, 7th edition. American Ornithologists' Union, Washington, D.C.
- Kaufman, K. 1996. Lives of North American Birds. Houghton Mifflin, Boston.
Global Range: (20,000-2,500,000 square km (about 8000-1,000,000 square miles)) BREEDING: southwestern Oregon south through coastal California to Santa Barbara County. NON-BREEDING: Baja California and Sinaloa to Distrito Federal. RESIDENT: southern California (Channel Islands and Palos Verdes Peninsula) (AOU 1983).
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)
Biogeographic Regions: nearctic (Native )
occurs (regularly, as a native taxon) in multiple nations, but breeds in a single nation
Regularity: Regularly occurring
Type of Residency: Breeding
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)
Average mass: 3 g.
Other Physical Features: endothermic ; bilateral symmetry
Average mass: 3 g.
Average basal metabolic rate: 0.06853 W.
Length: 10 cm
Weight: 3 grams
The Allen's Hummingbirds can be found in bushy woods, gardens, flower filled mountain meadows, and parks.
(Cassidy 1990, Stokes 1996)
Terrestrial Biomes: savanna or grassland ; forest
Habitat and Ecology
Comments: Chaparral, thickets, brushy hillsides, open coniferous woodlands, and gardens near coast, often in ravines and canyons. Nests on twig or fork of tree or shrub, sometimes on stalk of plant, among in vines, occasionally in building. In one area nested in live oaks, usually 2-4 m above ground; in another study, nested mostly in eucalyptus at average height of 5.5 m. In migration and winter also in open situations with flowering shrubs (AOU 1983).
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.
Arrives in central California by late January-early February (Terres 1980), southward migration occurs in July-August (Small 1974).
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)
Comments: Flower nectar (wide variety of sources) and insects (some of which obtained by hawking).
Defends feeding territory (small, numerous, often contested) and mating territory (larger, more formally defined). May compete for resources with Anna's hummingbird (CALYPTE ANNA) during breeding season.
Life History and Behavior
Perception Channels: visual ; tactile ; acoustic ; chemical
Status: wild: 48 months.
Lifespan, longevity, and ageing
Female Allen's hummingbirds usually start building their nest before they mate. After mating the female alone has to finish the half built nest. She uses moss, bits of vegetation, spider webs, bark flakes, and pine needles to finish the cup-shaped nest. This nest is only about 4 cm (1.5 in.) from top to bottom and 4-5 cm (1.5-2 in.) in diameter. She lays only two eggs, which are about 1 cm (1/2 in.).
The female alone incubates the eggs for about 16 to 22 days. Once the baby hummingbirds are hatched, the mother fearlessly protects her young. She alone has the duty to feed them until they are ready to leave the nest. She feeds them by inserting her bill into the baby's mouth and regurgitating food from her crop. Chicks usually fledge (leave the nest) in about 22 days and are immediately independant of their mother.
(Baicich 1997, Ehrlich 1988, Terres 1980, Stokes 1989)
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average time to hatching: 16 days.
Average eggs per season: 2.
In central California, males establish territory mid-Febryary to late March, nesting over usually by mid-July. Clutch size 2. Incubation reportedly 15-17 or 17-22 days, by female. Young tended by female, fledge in about 22 days. Two broods/year in central California.
Molecular Biology and Genetics
Barcode data: Selasphorus sasin
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Selasphorus sasin
Public Records: 3
Specimens with Barcodes: 6
Species With Barcodes: 1
US Federal List: no special status
CITES: appendix ii
IUCN Red List of Threatened Species: least concern
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N5B - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Relevance to Humans and Ecosystems
There is neither positive nor negative economic importance for the Allen's Hummingbird, but they do help in the pollination of flowers.
The Allen's hummingbird (Selasphorus sasin) is a species of hummingbird. The Allen's hummingbird is a small bird, with mature adults reaching only 3 to 3½ inches (75 to 90 mm) in length. The male Allen's has a green back and forehead, with rust-colored rufous flanks, rump, and tail. The male's throat is also an iridescent orange-red. The female and immature Allen's hummingbirds are similarly colored, but lack the iridescent throat patch, instead having a series of speckles on their throat. Females are mostly green, featuring rufous colors only on the tail, which also has white tips. The immature Allen's hummingbirds are so similar to the female rufous hummingbird that the two are almost indistinguishable in the field. Both species' breeding seasons and ranges are common factors used to differentiate between the two species in a particular geographical area.
The Allen's hummingbird is common only in the brushy woods, gardens, and meadows of coastal California from Santa Barbara north, and a minuscule portion of lower Oregon. The nominate race of Allen's hummingbird S.s. sasin is migratory, and winters along the Pacific coast of central Mexico. A second race S.s. sedentarius is a permanent resident on the Channel Islands off southern California. This population colonized the Palos Verdes Peninsula of Los Angeles County in the 1960s and has since spread over much of Los Angeles and Orange Counties.
The courtship flight of the male Allen's hummingbird is a frantic back and forth flight arc of about 25 feet (7.5 m) similar to the motion of a swinging pendulum, followed by a high-speed dive from about 100 feet (30 m). The male is also highly aggressive and territorial. Hot-tempered despite its diminutive stature, a male Allen's hummingbird will chase any other males from its territory, as well as any other hummingbird species, and they have even been known to attack and rout predatory birds several times larger than themselves such as kestrels and hawks.
The Allen's hummingbird constructs its nest out of plant fibers, down, and weed stems, coating the nest with lichens to give it structure. The nest is placed above ground on a tree branch or the stalk or stem of a plant. The female lays two white eggs, which she will incubate for 15 to 17 days. The young will leave the nest about three weeks after hatching. The mother will continue to feed the fledglings for several more weeks, then the young are left to fend for themselves.
Like all hummingbirds, the Allen's hummingbird's high rate of metabolism requires it to feed frequently, about every hour. The Allen's hummingbird drinks nectar from flowers, as well as eating any small insects it finds crawling around the flower blossom, which provide it with needed protein.
The common name commemorates Charles Andrew Allen (1841–1930), American collector and taxidermist.
- BirdLife International (2012). "Selasphorus sasin". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- Ridgway, Robert (1909). "Hybridism and Generic Characters in the Trochilidae". Auk 26 (4): 440–442. doi:10.2307/4071292.
- Taylor, Walter P. (1909). "An instance of hybridization in hummingbirds, with remarks on the weight of generic characters in the Trochilidae". Auk 26 (3): 291–293. doi:10.2307/4070800.
Names and Taxonomy
Comments: Constitutes a superspecies with S. rufus (AOU 1983).