The Plain-capped Starthroat (Heliomaster constantii) inhabits from northwest Mexico to Costa Rica. Its place is in canopy and edge of dry and evergreen forest, also coffee plantations, second growth, dry scrub, and isolated savanna trees. Olders are 12 cm (4 inches) in height and 7.5 g in weight.
Above dark bronzy-green, with crown duskier. Chin and face dusky, and gorget iridescent rose-red to orange-red. Below is mostly dull gray, flecked with bronze-green laterally. Bill black, and feet dusky. Feeds on flowers of Erythrina.