Allen’s hummingbird (Selasphorus sasin) was named after Charles Andrew Allen (1841-1930), the American collector and taxidermist who first noticed this species in the U.S. and described it to American scientists. The hummingbird is a genus; it is a small bird, with mature adults only reaching a length of 76 to 89 mm (3 to 3.5 in). Coppery Allen’s Hummingbirds, orange and green overall. The coppery tail, eye patch, and abdomen of adult males contrast with their bronze-green back and deep reddish orange gorgets. Females and immatures with paler coppery sides are bronze-green above. Both have bits of bronze spotting on their throats, but in the middle of the throat, females have more spots and a small patch of reddish-orange. The hummingbirds of Immature Allen are so similar to the female rufous hummingbird, the two in the field are almost indistinguishable. The breeding seasons and ranges of the two species are common variables used in a specific geographical region to distinguish between the two species. Allen’s hummingbird is popular only in the brushy forests, gardens, and meadows of coastal California from Santa Barbara north, and southern coastal Oregon. Allen’s nominated race of hummingbirds, S. s. Sasin is migratory, wintering along central Mexico’s Pacific coast.
In Mexico, Morelos and Puebla, only the migratory nominate race that occurs in the northern range migrate to the south all the way to winter along the Pacific coast of Mexico and central Mexico. During July and August, they travel south and the majority will have arrived at their winter destination by the end of October. A frenzied back-and-forth flight arc of about 25 ft (7.6 m) is identical to the motion of a swinging pendulum, accompanied by a high-speed dive of about 100 ft (30 m) during which tail feathers emit a distinctive sharp flutter to further attract the female’s attention. The courtship flight of male Allen’s hummingbirds. Aggressive and territorial, male Allen’s hummingbirds like any other hummingbird species, can chase any other male from their territories and have even been known to strike and rout predatory birds, such as kestrels and hawks, many times larger than themselves. The breeding habitat of the Allen hummingbird includes “open or partially wooded areas, including brushy slopes, canyons, thickets of willow and dogwood, living oak stands, and chaparral.” They can also be found in gardens, mountain meadows filled with flowers, and parks. Out of plant fibers, down, and weed stems, Allen’s hummingbird builds its nest, covering the nest with lichens and spider webs to give it structure. The nest is placed on a tree branch or the stalk or stem of a plant above ground. One or two white eggs are laid by the female, which she incubates for 15 to 17 days. Around three weeks after hatching, the young leave the nest. For several more weeks, the mother keeps feeding the fledglings, then the young are left to fend for themselves. The Allen’s Hummingbird in Oregon and California has a very limited breeding range of 31,400 square kilometers, which includes coastal scrub habitats. It winters on the edge of forests and shrubby areas with many flowering plants in a small area of central Mexico. In the eastern United States and Canada, this species has also drifted far from its normal range and has emerged. While this species is known to have significantly declined since the 1960s, its approximate breeding population of 700,000 is still believed to be high enough to merit a conservation classification of Least Concern.