Allen’s Hummingbird, Selasphorus sasin
Allen’s Hummingbird, Selasphorus sasin, Female Individual. Photograph taken in the coastal region of Orange County California, June 2020. Photograph and identification courtesy of Dr. Tom Bartol, Carlsbad, California.
Allen’s Hummingbird, Selasphorus sasin, Male Individual. Photograph taken within a residential community in Hereford, Arizona, July 2017. Photograph and identification courtesy of Bob Behrstock, Sierra Vista, Arizona (naturewideimages.com).
Background and Identification
The Allen’s Hummingbird, Selasphorus sasin, is one of two subspecies of the family Trochilidae. The two subspecies are similar in morphology but vary drastically in migration. The subspecies in this article migrate for breeding while the other subspecies is nonmigratory. The namesake of this bird was a collector named Charles Allen from California.
The Allen’s Hummingbird is small in stature, weighing approximately 3 grams at maturity. They are sexually dimorphic, with males being more vibrant in color than females. Adult males have iridescent green on their crown, down to their mantel or rump. On the side of their head, their upper tail coverts, tail, and underside are reddish-brown. Their breast is white, fading into the reddish-brown toward the belly and flanks. The wings and parts of the tail are a deep blue, nearing black. When folded, they form a band from the breast to the tail. The throat of this hummingbird is a striking iridescent orange-red. The plumage is rounded and creates a scale-like texture on the throat and crown. The bill is straight and black. Adult females and juveniles are similar in coloring. They are duller and do not have striking throat coloration. They instead have a white throat with some brown spots. Common among hummingbirds, females care for the young without the male. The Allen’s Hummingbird female raises two to five broods of two young within a breeding season.
Habitat and Geographical Range
The Allen’s Hummingbird feeds on nectar from flowering plants. In their breeding range, they favor early-flowering shrubs like bush monkeyflower, currants, gooseberries, and plants such as Indian paintbrush and columbine. Males and females have different preferences in habitat during breeding season. Males create their territory in scrub vegetation near bodies of water, whereas females prefer more dense vegetation with tree cover for nesting. When females cross a male’s territory, he will present a mating display including shuttle flight (darting back and forth), and dive from about 30 m (100 feet) in front of her while producing different sounds. In their non-breeding season, they can be found in scrub clearings with flowers, close to the forest edge.
The Allen’s Hummingbird’s non-breeding range is in south-central Mexico, in Estado de Mexico and surrounding states. They migrate up the coastal and central regions of Mexico and Northern Baja California, through southern Arizona and California. They breed from central California to central Oregon.
Common Misidentifications
Identification is not straightforward because of the proximity to the Rufous Hummingbird, Selasphorus rufus. The green and black coloration on the heads of these two species is the best differentiating factor. Allen’s tend to have more green plumage present, sometimes covering their whole back, while Rufous tend to have less green and more reddish-brown. Allen’s also tend to have shorter wings and tails. Field identification may not always be accurate, especially for female individuals, and hybridization between these two species is likely.
Conservation Status
From a conservation perspective, the Allen’s Hummingbird is categorized by the IUCN as a Least Concern. However, the current population has a decreasing trend. The greatest threat is habitat loss within their limited breeding range. Despite this, they have been observed to adapt well to human-altered habitats. The latest population estimate is 700,000 individuals.