The Mangrove Hummingbird is endemic to Costa Rica and mainly lives in Pacific-coast mangroves, especially where Pelliciera rhizophorae is abundant.
Males are bronze-green above, with a bright blue-green throat and breast, a white abdomen, and a shallowly forked dark tail. Females are mostly white below, with bronze-green spots at the sides.
It takes nectar from Pelliciera flowers and eats insects; it also visits Lonchocarpus flowers and epiphytes. It sometimes enters neighboring forest edge and secondary growth.
An extinction-risk assessment has not been added yet.