ABSTRACT: From 1997 to 2001 we studied a group of 6 Trinidad piping-guans Aburria pipile, a critically endangered species, in northern Trinidad. The group occupied a home range of 19 ha in highly disturbed secondary forest and around small farms, and often split into smaller groups. They spent 93.6% of the time in the forest canopy >5 m above ground and only 0.2% of the time on the ground (n = 48.1 h). In early morning (n = 18.7 h), they spent 80.3% of their time perched alert, 9.3% preening, 3.9% flying, 3.6% walking, 2.4% feeding, 0.3% drinking, and 0.1% perched flapping. In late afternoon (n = 8.2 h), they spent 78.6% of their time perched alert, 12.8% preening, 3.7% walking, 3.0% feeding, 1.2% flying, and 0.7% drinking. At midday, they eluded observation. They foraged mostly on fruits (occasionally leaves or flowers) of 15 species of plants, with Virola surinamensis (Myristicaceae) constituting the primary item (33.3% of foraging bouts; n = 30). They drank water from epiphytic bromeliads. Drumming displays, produced mechanically by the wings in flight, were given intermittently throughout the morning and rarely in the afternoon. Singing occurred intermittently throughout the early morning and late afternoon. The song consisted of 3 to 7 plaintive whistles rising in pitch, delivered by lone individuals averaging 2.7 songs min^–1, in bouts of up to 30 min. Soft piping calls were usually given in a social context. Raised crest feathers appeared to be an aggressive display. Piping-guans rarely interacted with other species of birds. They were relatively unperturbed by human disturbance.