Brazilian ruby male showing its iridescent throat, Atlantic Rainforest, Brazil

The Brazilian ruby (Clytolaema rubricauda) is a species of hummingbird found in forest edge, second growth, gardens and parks in eastern Brazil. It is the only species placed in the genus Clytolaema. Although sometimes placed in the genus Heliodoxa, with the brilliants, the Brazilian Ruby is more typically treated as the sole member of a monotypic genus, Clytolaema, one of a great many hummingbird genera described by John Gould. It is common and among the species regularly seen at hummingbird feeders within its range. It is a relatively large hummingbird. Both sexes of this hummingbird are attractive and distinctive. Males are primarily clad in deep green, with a brilliant deep red throat patch, a small but obvious white postocular spot, browner wings, and a bright red tail, while females share the spot behind the eye and the tail color of the male, but are otherwise rich orange over the entire underparts and on the rump. The male is overall green with a coppery back and rump, a coppery-rufous tail and, as suggested by its common name, a highly iridescent ruby throat that can appear black from some angles. Females are green above and cinnamon below. Both sexes have a white post-ocular spot and a straight black bill.

As its vernacular name suggests, this species is endemic to Brazil, where it generally occurs from Minas Gerais south to Rio Grande do Sul, and it occurs in wooded areas of all types in the Atlantic Forest region, to at least 2000 m. It regularly visits feeders in small numbers. The Brazilian Rubys primarily feed on nectar taken from a variety of brightly colored, scented small flowers of trees, herbs, shrubs and epiphytes. They favor flowers with the highest sugar content (often red-colored and tubular-shaped) and seek out, and aggressively protect, those areas containing flowers with high energy nectar.They use their long, extendible, straw-like tongues to retrieve the nectar while hovering with their tails cocked upward as they are licking at the nectar up to 13 times per second. Sometimes they may be seen hanging on the flower while feeding.

Many native and cultivated plants on whose flowers these birds feed heavily rely on them for pollination. The mostly tubular-shaped flowers actually exclude most bees and butterflies from feeding on them and, subsequently, from pollinating the plants. Males establish feeding territories, where they aggressively chase away other males as well as large insects – such as bumblebees and hawk moths – that want to feed in their territory. They use aerial flights and intimidating displays to defend their territories.