Large hummingbird with a stout bill. Male has a black belly and a black throat that is bordered below by violet; throat may appear all dark from some angles. Female has golden-green underparts, a violet throat patch, and conspicuous buffy mustache stripe. Inhabits humid lowland and foothill forest east of the Andes; sometimes visits feeders. Song is quite unusual: a descending, rattling trill that can last over five seconds.