The nominate male has bright metallic grass green upperparts that is more bronzy on the uppertail coverts.

Their underparts are more yellowish green, and the black tips of the outer tail feathers are less sharply defined.

[8] Subspecies E. e. nelsoni of the stripe-tailed hummingbird is the northernmost; it is found in the eastern Mexican states of Veracruz and Oaxaca.

The nominate E. e. eximia is found from Chiapas in extreme eastern Mexico south through southern Belize, Honduras, and El Salvador into central Nicaragua.

Subspecies E. e. egregia is found on both the Caribbean and Pacific slopes in Costa Rica and western Panama.

[8] The stripe-tailed hummingbird inhabits the edges and interior of humid montane, semi-deciduous, and pine-oak forest and also plantations.

It makes a cup nest of plant down with lichens (especially red ones) on the outside, and typically places it 1 to 3 m (3 to 10 ft) above the ground near a stream.

The stripe-tailed hummingbird's song is "1-3 squeaky, sometimes metallic notes, then a low, dry, insectlike trill, then 1-3 more squeaks".