Last updated: May 21, 2021
Selasphorus sasin sedentarius
Allen's hummingbird, Selasphorus sasin sedentariusis, an endemic subspecies found on all of the islands in Channel Islands National Park, with the exception of Santa Barbara Island. It is also a permanent resident on Santa Catalina and San Clemente Islands. In the 1960's, sedentarius likely dispersing from Santa Catalina Island, colonized the Palos Verdes Peninsula of Los Angeles County. Since that initial colonization, S.s. sedentarius has spread over much of Los Angeles and Orange Counties.
Quick and Cool Facts
- Before receiving its present name, S.s. sedentarius was called non-migratory Allen's hummingbird.
- The endemic species found on the Channel Islands, S.s. sedentarius, differs from the mainland species S.s. sasin, by having a longer wing, tail and bill.
- During the breeding season, males defend territories in mixed shrubs and woods located in coastal canyons. Allen's hummingbirds have even been seen chasing red-tailed hawks and American kestrels from their territories.
- In the 1960's S.s. sedentarius was discovered nesting on the Palos Verdes Peninsula, which initially was perplexing.Through investigation, it was theorized that the ornamental non-native plants such as the eucalyptus and bottlebrush have played a role in this increased range.
- Recently, S.s. sedentarius has spread its range across the L.A. Basin, and beyond. They have also moved into Orange County to the south, and even into thevalleys neighboring the coastal plain.
- The recent colonization of S.s.sedentarius on San Miguel Island in the mid-20th century may be a recolonization of habitat that was once destroyed by grazing.
- Contrary to published accounts, Allen's Hummingbirds do not sound like the similar appearing Rufous hummingbirds. S.s. sedentarius is very different vocally as well as mechanically with the "wing whistle" and "tail pops".
The Allen's hummingbird is a small bird, with mature adults reaching only 3 to 3½ inches in length, although the subspecies on the Channel Islands, S.s. sendentarius, is slightly larger, and also has a longer wing, tail and bill. 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.
Allen's hummingbird S.s. sasin, the nominate species, is migratory, and winters along the Pacific coast of central Mexico. The second race, S.s. sedentarius, is a permanent resident on the Channel Islands off southern California. In the 1960s, this population colonized the Palos Verdes Peninsula of Los Angeles County and has since spread over much of Los Angeles and Orange Counties.
S.s. sedentarius inhabits chaparral and riparian woodlands below 1000 feet in elevation. Interestingly, due to its expansion to the mainland, it now inhabits a mixed urban habitat. The more widely distributed subspecies, S.s. sasin, inhabits mixed evergreen, riparian woodlands, eucalyptus and cypress groves, oak woodlands, and coastal scrub areas in breeding season. The broad array of landscape horticulture found in residential gardens, in particular the fuchsia plantars; provide a substantial year-round food source of desirable nectar.
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 courtship flight of the male Allen's hummingbird is a frantic back and forth flight arc of about 25 feet similar to the motion of a swinging pendulum, followed by a high-speed dive from about 100 feet. 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.
Males maintain territories that overlook open coastal scrub or riparian shrubs where they perch in conspicuous places. Females choose nest sites in areas where there is more tree cover. They locate the nest in shrubs and trees with dense vegetation such as vines and thickets anywhere from 2 feet to 45 feet off the ground.
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. On average the female lays two dull white eggs, which are incubated for 12-22 days. S.s. sasin usually lays two clutches per season; however, S.s. sedentarius will lay more. 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.
Although this species may have a restricted range, it is not believed to be vulnerable. The population size is very large, and hence does not approach the thresholds for vulnerable under the population size criterion. Recent surveys within the park indicate that there is an increasing trend with yearly fluctuation. For these reasons the species is evaluated as Least Concern by the International Union for Conservation of Nature.
- The Hummingbird Book: The Complete Guide to Attracting, Identifying, and Enjoying Hummingbirds By Donald Stokes, Donald W. Stokes, Lillian Q. Stokes