SummaryHummingbirds in the tropical rainforests of southwestern Costa Rica face intense competition from stingless beesTrigonathat steal nectar from hummingbird flowers. Here we document both interference and exploitative competition between bees and hummingbirds at scarlet, hummingbird pollinated flowers ofPassiflora vitifolia. Aggressive stingless bees prevented Long‐tailed Hermit HummingbirdsPhaethornis superciliosusfrom feeding at nearly one‐third of the passion flowers approached. In exclusion experiments, bees and hummingbirds each removed most of the nectar from treated flowers. Experimental exclusion of bees also increased hummingbird use of both natural and artificial flow