The species prefers nectar of flowers from the buttressed Tea Mangrove Pelliciera rhizophorae. It also eats insects (Ridgley and Gwynne 1989). In an ongoing study, Elizabeth Jones and Abraham Gallo have observed the Mangrove Hummingbird feeding at flowers of an Inga sp. (Fabaceae), the purple flowers of a vine (Maripa nicaraguensis, Convolvulaceae), as well as Heliconia sp. (Heliconiaceae) flowers in a forest clearing within 200 m of the mangrove edge (D. J. Lebbin, personal communication).