Very little detailed information. Plain-capped Starthroat forages at all heights, but commonly perches on a high, exposed twig. Captures small insects by flycatching from a high perch,and also by gleaning (Stiles and Skutch 1989, Howell and Webb 1995).
Very little information. Plain-capped Starthroat was described as foraging by traplining (i.e., following a "regular feeding route between successive patches of flowers at low low densities") rather than defending feeding territories (Des Granges 1979). Male Plain-capped Starthroats sometimes defend flowering Erythrina (Stiles and Skutch 1989).
Little information. Plain-capped Starthroat is polygynous, as are most if not all species of hummingbirds (Schuchmann 1999: 509).
Social and interspecific behavior
Plain-capped Starthroat usually is solitary, as is typical of hummingbirds. At one site in southern Mexico, two thirds of observed agonistic interactions (chases) were intraspecific (Des Granges 1979). In interspecific interactions (chases) at this site, Plain-capped Starthroat was the "winner" in interactions over Broad-billed Hummingbird (Cynanthus latirostris), Violet-crowned Hummingbird (Amazilia violiceps), and Rufous Hummingbird (Selasphorus rufus), and the "loser" in interactions with Violet-crowned Hummingbird and with Archilochus sp. (Note that Plain-capped Hummingbird was both a winner and loser in interactions with Violet-crowned Hummingbird). Witzeman (1979) reported that a Plain-capped Starthroat (sex?) was subordinate to an Anna's Hummingbird (Calypte anna).
No documented reports of predation on Plain-capped Starthroat?