Red-billed emerald

The red-billed emerald (Chlorostilbon gibsoni) is a species of hummingbird in the "emeralds", tribe Trochilini of subfamily Trochilinae. It is found in Colombia and Venezuela.

The red-billed emerald is 7.6 to 9 cm (3.0 to 3.5 in) long and weighs about 2.8 g (0.099 oz). The males of all three subspecies have a straight bill with a mostly red mandible. The females' mandibles are red at the base. The bills are about 1.3 cm (0.51 in) long. Males of the nominate subspecies have dark bronze-green upperparts and a deeply forked blue-black tail. Their faces and underparts are glittering green to golden green. Nominate females are shining green above and plain gray below with dusky cheeks and a short white line behind the eye. Their central tail feathers are dark blue-green and the rest dark green with dusky ends and narrow gray-white tips.

Subspecies C. g. chrysogaster is larger than the other two subspecies. The male is mostly malachite green; its tail is slightly bluer and more deeply forked than the others'. C. g. nitens is very like the nominate, but with a slight gold sheen and a less deeply forked tail.