About Lampornis clemenciae (R.Lesson, 1830)
Lampornis clemenciae, commonly called the blue-throated mountaingem, is the largest hummingbird found in the United States. It measures 11.2 to 12.8 cm (4.4 to 5.0 in) in length. Males have an average weight of 8.4 g (0.30 oz), while females average 6.8 g (0.24 oz). Both sexes have a medium-length black bill, with some variation across subspecies, and females have longer bills than males. All subspecies of both sexes have a noticeable white stripe behind the eye, plus a narrower stripe that extends backward from the corner of the bill, underneath a blackish cheek patch. The nominate subspecies is the largest and has the longest bill. Adult males of the nominate subspecies have an iridescent cobalt to cerulean blue gorget with a narrow buffy gray edge. Their upperparts are mostly bright greenish bronze, becoming dark bronzy olive on the rump. Their underparts are medium brownish gray, with some 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 gorget and have entirely medium gray underparts. Subspecies L. c. phasmorus is the smallest and has the shortest bill. Its upperparts are bright green rather than greenish bronze. Males of this subspecies have cold gray rather than brownish gray underparts, while females have dark gray underparts. The iridescence on the sides of the breast is green. The white tips on its tail feathers are wider than those of the nominate subspecies. Subspecies L. c. bessophilus falls between the other two subspecies in size. Its upperparts are duller than the nominate's, with less bronze mixed into the green. Males have brownish gray underparts and females have medium pale gray underparts; like the nominate, it has some greenish bronze iridescence on the sides of the breast. The white tips on its tail feathers are the narrowest of all three subspecies. The nominate subspecies of blue-throated mountaingem has the largest distribution range. It occurs in Mexico's Sierra Madre Oriental and central plateau, extending as far south as Oaxaca. L. c. bessophilus is found in southeastern Arizona and the northwestern Mexican states of Sonora, Chihuahua, and Durango. L. c. phasmorus is confirmed to live only in the Chisos Mountains of southern Texas, where it breeds, and its non-breeding range has not been documented. Birds in the northern Mexican state of Nuevo León may also belong to this subspecies rather than the nominate. The blue-throated mountaingem inhabits a variety of moist forest landscapes. In the United States and northern Mexico, it lives in riparian forest (often in canyons), pine-oak forest, and mixed coniferous forests. In central and southern Mexico, it tends to prefer coniferous forests. In Arizona, it is found in "sky island" mountain ranges, and it rarely occurs below 1,300 m (4,300 ft) in elevation. Near Mexico City, it occurs between 3,600 and 3,900 m (11,800 and 12,800 ft), and in Oaxaca it occurs between 2,500 and 3,000 m (8,200 and 9,800 ft).
