The birds are approximately 13 centimetres (5.1 in) in length with fairly long, slightly decurved black bills.

The male usually has an iridescent green throat, or bluish-purple in the Ecuadorian hillstar, with dull greenish upperparts and pale flanks.

These highly territorial hummingbirds are found in temperate and alpine grassland, scrub and woodland at altitudes of 1,200 to 5,200 metres (3,900 to 17,100 ft).

The Ecuadorian hillstar has been observed nesting at high altitudes on the cliffs of Cotopaxi.

[4] Many hillstars feed mainly on shrubs of the Andean plant genus Chuquiraga, and some species may be limited to them.