Large, dark hummingbird. Common in tepui highlands. Male is mostly shining green, especially on the throat, breast, and forehead; female is white below with extensive green spotting. Both sexes have conspicuous white spot behind eye. Occurs in a wide variety of habitats including tall forest, edge, and open scrub at middle and high elevations (above 800 m) in tepui region. Feeds on nectar and defends patches of flowers from other hummingbirds. Gives loud, sharp chip note while foraging. No other large, green hummingbird occurs in its limited range.