Association of Birds with Monkeys in Costa Rica

Abstract

Double-toothed kites (Harpagus bidentatus), gray-headed tanagers (Eucometis pencillata), and tawny-winged woodcreepers (Dendrocincla anabatina) forage in association with squirrel monkey (Saimiri oerstedi) troops in Parque Nacional Corcovado, Costa Rica, throughout the year, based on field work conducted from February to September 1982 and from June 1983 to September 1984. These species and other occasional attendants fed on arthropods and small vertebrates flushed by the monkeys. Censuses indicated that kites, tanagers, and woodcreepers spent roughly twice as much time following squirrel monkeys during the wet season, when arthropod availability was lowest, than at other times of the year. Bird attendance frequency was greatest in the morning during the wet season, but time of day differences were less distinctive in other seasons. Attendance frequencies were greater when squirrel monkey troops were foraging and travelling than resting and still. Kites at this site also followed capuchin monkeys (Cebus capucinus), but appeared to prefer squirrel monkeys.