Selasphorus sasin

Constitutes a superspecies with S. rufus (AOU 1983).

Relatively small breeding range in coastal and southern California and southwestern Oregon; restricted winter range mostly in Mexico; large population size; still widespread and relatively common in historical range, and has expanded range in southern California; no major threats; commonly uses altered habitats and urbanized areas with cultivated flowering plants.

Breeding range extends from southwestern Oregon southward through all of coastal southern California (and recently expanding inland), including several of the Channel Islands where the species is resident (AOU 1998, Clark and Mitchell 2013). Winter range is mostly in central Mexico south to Distrito Federal, perhaps north to Aguascalientes and Guanajuato; the species also occurs casually along the Gulf Coast in southeastern Texas, southern Louisiana, Mississippi, Alabama, and Georgia (AOU 1998). The percentage of the population that winters in central Mexico is unclear, as is the whereabouts of the remaining wintering population (Phillips 1975). Migrants pass through southern Califomia and northern Baja California (including Los Coronados and Cedros islands), most of northwestern and north-central Mexico, and range east, at least casually, to southern Arizona and southern New Mexico (AOU 1998).

The number of distinct occurrences or subpopulations has not been determined using standardized criteria, but this species is represented by a very large number of observation/collection sites (e.g., see GBIF database, eBird) and locations (as defined by IUCN).

Some habitat has been lost to intensive development, but in many other areas habitat changes (especially addition of nectar-producing ornamental plants, as well as feeders) associated with residential and urban development have increased hummingbird food resources beyond natural levels, and Allen's hummingbird readily breeds in such disturbed habitats, including urban parks or eucalyptus groves (Clark and Mitchell 2013).

This species may be flexible enough to adjust to drought and other potentially deleterious aspects of climate change. For example, migration timing varies annually, depending on the timing of winter rains, which influences nectar availability; drought can delay migration by 10-14 days (Clark and Mitchell 2013).