The Green-breasted Mango is a relatively large hummingbird of tropical American lowlands, found around forest edges and clearings.
The adult male has an all-green body. The female is white below with a diffuse dark stripe down the center and white spots at the tail tips.
During the first feather change, 0–2 inner feathers covering the wing were replaced (mean 0.20). Young wing feathers are duller and less shiny than later feathers. Males develop a rainbow sheen on the body only after a second major feather change.
Records of nesting females include male-like body color, with no intermediate colors noted. Fine lines across the beak were gone by the second feather change. Adults molted from June to November; young birds molted throughout the year. Its timing may relate to when young leave the nest and to birds that take a long time to replace their feathers. Feather color, beak marks, and timing each changed at a different stage.
An extinction-risk assessment has not been added yet.