Selasphorus platycercus

Phylogeographical analyses and population genetics methods revealed that migratory populations in the USA and sedentary populations in Mexico of the platycercus subspecies form one admixed population, and that sedentary populations from southern Mexico and Guatemala (guatemalae) undertook independent evolutionary trajectories (Malpica and Ornelas 2014).

Large range extent and area of occupancy in western United States and Mexico; large population size; relatively stable or slowly declining; no known major threats, though further study of climate change impacts related to altered phenology of food resources and migration in the northern portion of the range is needed.

Breeding occurs in the mountains from central Idaho, southern Montana, and northern Wyoming south to southeastern California, northeastern Sonora, Guanajuato, Mexico, Distrito Federal, Hidalgo, Nuevo León, and western Texas; and in eastern Chiapas and Guatemala (rare in eastern mountains) (AOU 1998, Camfield et al. 2013); nesting may occur in extreme eastern Oregon, north-central Idaho, and in the Black Hills of South Dakota/Wyoming, but neither nests nor eggs have been recorded there in recent years (see Camfield et al. 2013). Winter range extends from the highlands of northern Mexico south to western Veracruz and Oaxaca (west of the Isthmus of Tehuantepec), in the breeding range in Chiapas and Guatemala, and rarely but regularly to coastal Texas and southern Louisiana, casually to southern Mississippi, southern Alabama, Georgia, and also southern Arizona (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).

No major threats are known. Over the short term, deforestation may provide enhanced food resources if suitable nectar sources increase in clearings and along forest edges, though subsequently an increase in forest cover may reduce hummingbird food resources and populations. For example, in high-desert riparian habitat in Oregon-Nevada, a broad-tailed hummingbird population decreased in abundance 10 years after cattle removal, apparently owing to decrease in abundance of flowering plants with increasing forest growth (Earnst et al. 2005). Similarly, increase in forest cover due to fire suppression could reduce local hummingbird food resources and populations.

In west-central Colorado, climate change is affecting the phenology of hummingbird nectar resources, and this eventually could lead to contraints on hummingbird breediing success; similar phenological changes were not found in southern Arizona (McKinney et al. 2012). McKinney et al. (2012) characterized west-central Colorado as near the northern limit of the breeding range and suggested that continued climate change there could make the area unsuitable for broad-tailed hummingbird breeding; they suggested that this climate-change-driven phenological alteration, combined with increased warming at lower latitudes, could result in an overall shrinkage of the species' breeding range through contraction at the northern end of the range. However, west-central Colorado is well south of the northern limit of the breeding range (which extends several hundred kilometers farther north into southern Idaho, northern Wyoming, and southern Montana), and available Breeding Bird Survey data (though not well suited to hummingbirds) suggest that although Colorado hummingbird populations may be declining, the northernmost breeding populations actually may be increasing, and the species remains widespread and relatively common in historical habitat in areas north of Colorado. Thus further study of potential climate-change impacts is warranted. See Malpica and Ornelas (2014) for a discussion of long-term (thousands of years) impacts of climate change on broad-tailed hummingbird distribution and populations.