About Basilinna leucotis (Vieillot, 1818)
The white-eared hummingbird (Basilinna leucotis) is 9 to 10 cm (3.5 to 3.9 in) long. Males weigh an average of 3.6 g (0.13 oz), and females weigh an average of 3.2 g (0.11 oz). Adult individuals of the species' three subspecies are very similar to one another. All individuals have straight bills; males have red bills with black tips, while females' bills are mostly blackish with some red to orange coloring at the base.
For the nominate subspecies, breeding-plumage males have a metallic violet or bluish violet forehead, a mostly black face with a wide white stripe behind the eye, and a dull black crown. Their upperparts are bright metallic green to bronze green, and uppertail coverts are more bronzy; the rump and covert feathers have rusty edges. The central pair of tail feathers is bright bronze green, the next pair is darker green, and the remaining three pairs are bronzy black with bright bronze green tips. Their chin and upper throat are violet blue, the lower throat is metallic emerald green, and the breast and flanks are bronze to bronze green with dull grayish white running down the center. Undertail coverts are grayish brown with a faint bronze gloss.
Breeding-plumage females of the nominate subspecies resemble males, but they have a dusky brown crown and lack the brilliant coloring on the chin and throat that males have. Their underparts are pale brownish gray to grayish white with metallic bronze green spots, and their undertail coverts are grayish with whitish margins. Their central tail feathers have brownish gray tips.
The subspecies B. l. borealis is somewhat larger than the nominate subspecies, and males have much more white and less green on their underparts. B. l. pygmaea is somewhat smaller than the nominate subspecies, with less green on the lower throat and more white on the underparts.
In terms of distribution and habitat, the B. l. borealis subspecies occurs from southern Arizona into the Mexican states of Sonora, Chihuahua, and Tamaulipas. It is an occasional visitor to New Mexico and Texas, and has occurred as a vagrant further north and east in the United States. The nominate subspecies B. l. leucotis is found from central and southern Mexico into Guatemala. B. l. pygmaea is found in El Salvador, Honduras, and Nicaragua.
The white-eared hummingbird is a species of montane regions. It inhabits the interior, clearings, and edges of pine, pine-oak, and pine-evergreen forest. Its elevational range is between 1,200 and 3,500 m (3,900 and 11,500 ft).
