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. == Taxonomy and systematics == The red-billed emerald was originally described as a species and later treated as a subspecies of the blue-tailed emerald (Chlorostilbon mellisugus). Since the early 2000s, most taxonomist have again treated it as a species in its own right. It has also at times been considered conspecific with the western emerald (C. melanorhynchus). As currently (2020) understood, the red-billed emerald has three subspecies: the nominate C. g. gibsoni, C. g. chrysogaster, and C. g. nitens. == Description == 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…