Frugivores (Fruit-eaters) such as pigeons are important ecosystem service providers in tropical forests, but are seriously threatened. Five species of bleeding-heart pigeons occur only in the Philippines: Luzon bleeding-heart Gallicolumba luzonica (Near Threatened, IUCN Red List), Mindoro bleeding-heart G. platenae (Critically Endangered), Mindanao bleeding-heart G. criniger (Vulnerable), Sulu bleeding-heart G. menagei (Critically Endangered), and Negros bleeding-heart G. keayi (Critically Endangered). These bleeding-hearts are excellent ambassador species for the highly threatened forest habitats in the Philippines. Population levels and ecological requirements of all these species are poorly known owing to their cryptic and elusive behaviour and lack of study to date. With the continuing deterioration of suitable habitats, coupled with persistent local trapping and wildlife trade in the country, their populations remain highly threatened. The fact that all five Philippine bleeding-hearts are globally red-listed and three of them are in the highest category of threat is an indication that major, but as yet, unclarified forces are seriously constraining their populations. It is likely that the following factors work in combination to render the species very rare : (1) lowland forest habitat loss in general, (2) the increasing rarefication of some particular microhabitat such as thick patches of leaf-litter (as the species forage largely on the ground), (3) the unquantified effects of predation by exotic mammals (notably rats), and (4) the unquantified effects of killing for food by local hunters. The main thrust of the proposed research will be to identify the various contributions of these anticipated constraints and hence to determine the optimal management solutions to begin to recover the populations.