Their chin and upper throat are violet blue, the lower throat metallic emerald green, and the breast and flanks are bronze to bronze green with dull grayish white down the center.

[8] The white-eared hummingbird's 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 U.S.

The white-eared hummingbird is a species of montane regions where it inhabits the interior, clearings, and edges of pine, pine-oak, and pine-evergreen forest.

[8] The white-eared hummingbird forages for nectar at a very wide variety of flowering plants and shrubs, mainly feeding in the low to mid-levels of the vegetation.

It also makes "secretive low approaches" to feed in the territories of significantly larger species like Rivoli's hummingbird (Eugenes fulgens).

[8] The white-eared hummingbird's breeding seasons vary with latitude, from March to August in the north to October through December in El Salvador.

It is typically placed up to 6 m (20 ft) above the ground in a tree or shrub, and several nests may be short distances apart.

Its calls have been described as "fairly hard, dry chips, at times repeated steadily, [that] may break into short, quiet gurgles" and "a sharp metallic tchik or tink".