There is currently immense interest in restoring tropical forests to achieve environmental and social goals, especially carbon sequestration. More than half of tropical forest area globally is already second growth. Yet the future of these forests is uncertain. The recovery of old-growth tree species, which tend to have denser wood and store more carbon, partly depends on the wildlife species present and their interactions with tree seeds. Using a combination of field experiments and camera trapping in southern Costa Rica, I found that seed predation by rodents and granivorous birds represented a substantial bottleneck for later-successional seeds arriving at restoration sites. Sites with fewer seed predators could favor the tree establishment, but only if sufficient seeds arrive.