Manakins are prominent fruit-eaters and seed dispersers in the Neotropics. Most manakin species establish lek areas where males devote long periods of time displaying to attract mates, interspersed with brief absences to feed on fruits located near lek areas. We compared the frequency of visits to plants, fruit handling behavior, and number of fruits ingested by the lek-forming Manacus manacus (White-bearded Manakin) and species of non-lekking birds in two species of fruiting trees (Miconia rigidiuscula and Ocotea pulchella) in lek and non-lek areas during the lek and non-lek periods of M. manacus in a threatened Atlantic forest ecosystem. During the non-lek season, M. manacus and non-lekking birds did not differ in the frequency of visits to Miconia trees near lek and non-lek areas. However, M. manacus swallowed a higher number of fruits near leks than non-lekking birds, while the opposite was true in non-lek areas. During the lek season, M. manacus visited Ocotea trees more frequently and swallowed more fruits than non-lekking birds in lek areas. No birds were recorded on Ocotea trees in non-lek areas. This study provides an example of context dependence in the quantity component of seed dispersal effectiveness in which the lek breeding system of a frugivorous species influences the identity of seed removers and the quantity of seeds removed in and around lek areas.