SummaryBare-necked Umbrellabird Cephalopterus glabricollis is endemic to Costa Rica and western Panama. It eats fruit, breeding at high elevations (> 800 m) and migrating to lower elevations during the non-breeding season. Using data from transect counts and radio-telemetry, we monitored bird movements in a protected area (Monteverde-ArenalSan Ramón reserves) in the Tilarán Mountains, Costa Rica. We also monitored fruit abundance along an altitudinal gradient to explore the potential relationship between bird movements and the abundance of the fruits this species consumed. The presence and abundance of umbrellabirds at high elevations (1,400 m) during the breeding season (March-June) coincided with the highest peak of fruit abundance. The presence of umbrellabirds in the lowlands (400 m) during the non-breeding season overlapped with the period of highest fruit abundance at these elevations. At middle elevations, bird presence and abundance did not correlate with fruit abundance. Radio-tagged birds left the protected area during the non-breeding season and there were no umbrellabirds inside the protected area during this period. Habitats where this species bred were well represented in the protected area but the habitat where they spent the non-breeding season was poorly represented, and was not adequately protected. This represents a potential threat to this species in the Tilarán Mountains.