Amethyst-throated Mountaingem

The Blue-throated Mountaingem, known scientifically as Lampornis clemenciae, is a striking species of hummingbird belonging to the tribe Lampornithini within the subfamily Trochilinae. This bird is notable for being the largest hummingbird species found within the United States.

Identification Tips

Adult males of this species can be identified by their iridescent cobalt to cerulean blue throat patch, or gorget, which is bordered by a narrow buffy gray margin. Both sexes exhibit a conspicuous white stripe behind the eye and a narrower stripe extending backward from the corner of the bill beneath a blackish cheek patch. The upperparts are a bright greenish bronze, transitioning to a dark bronzy olive on the rump, while the underparts are a medium brownish gray with greenish bronze iridescence on the sides of the breast. The tail is black with faint indigo iridescence and white tips on the outer two pairs of feathers. Females lack the blue gorget and have entirely medium gray underparts.

Habitat

The Blue-throated Mountaingem inhabits a variety of moist forest landscapes, including riparian forests, pine-oak forests, and mixed coniferous forests. In the United States and northern Mexico, it is often found in canyons, while in central and southern Mexico, it prefers coniferous forests.

Distribution

This species has a broad range, with the nominate subspecies found in Mexico's Sierra Madre Oriental and central plateau, extending as far south as Oaxaca. The subspecies L. c. bessophilus is located in southeastern Arizona, southern New Mexico, and northwestern Mexico. L. c. phasmorus is known from the Chisos Mountains of southern Texas.

Behaviour

The Blue-throated Mountaingem exhibits migratory behavior, with northern subspecies moving south for the winter. Some individuals remain at feeding stations in southeastern Arizona throughout the winter. The central and southern Mexican populations are thought to move to lower elevations during winter.

Song & Calls

Males sing two types of songs: a simple "peep song" and a complex "whisper song." The female also sings during the breeding season. The male's song includes sharp atonal trills and clicks, with a vocal range of 1.8 to 30 kHz. Ultrasonic vibrations produced by the bird may serve to flush out insect prey.

Breeding

Breeding seasons vary across the range of the Blue-throated Mountaingem. The female alone constructs the nest from soft plant fibers and spider silk, camouflaging the exterior with green mosses or lichens. The female incubates the two white eggs for 17 to 19 days, with fledging occurring 24 to 26 days after hatching.

Diet and Feeding

The Blue-throated Mountaingem forages for nectar from a wide variety of flowering plants and is also known to feed on small arthropods and sap from wells created by the Red-naped Sapsucker.

Conservation status

The IUCN has assessed the Blue-throated Mountaingem as being of Least Concern, with a stable population of about 2,000,000 mature individuals. The species is highly tolerant of human activity, though its uncommon status in the northern part of its range makes it vulnerable to habitat damage.