White-chested Emerald

The white-chested emerald (Chrysuronia brevirostris) is a hummingbird in the "emeralds", tribe Trochilini of subfamily Trochilinae. It is found in Brazil, the Guianas, Trinidad, and Venezuela. == Taxonomy and systematics == The white-chested emerald's taxonomic history is complex. The species was previously known in succession as Amazilia chionopectus, Agyrtria brevirostris, and Amazilia brevirostris. A molecular phylogenetic study published in 2014 found that Amazilia was polyphyletic. In the revised classification to create monophyletic genera, the white-chested emerald was moved by most taxonomic systems to Chrysuronia. However, BirdLife International's Handbook of the Birds of the World retains it in Amazilia. The white-chested emerald has three subspecies, the nominate C. b. brevirostris, C. b. chionopectus, and C. b. orienticola. == Description == The white-chested emerald is 9 to 10 cm (3.5 to 3.9 in) long. Males weigh about 4.6 g (0.16 oz) and females 4.4 g (0.16 oz). Adults of both sexes of all subspecies have a short, straight, blackish bill and the sexes are almost alike in plumage. The nominate subspecies has iridescent turquoise-green crown and cheeks and shining bronze-green upperparts that become coppery on the rump. Its central tail feathers are coppery and the outer ones bronze to copperish with blackish…