SOCIAL BEHAVIOUR AND ROLE OF THE COMMUNAL ROOST AS AN 'INFORMATION-CENTRE' IN CAPTIVE WHITE-VENTED MYNAS, ACRIDOTHERES JAVANICUS (CABANIS)

Abstract

White-vented Mynas (Acridotheres javanicus) formed nearly linear social hierarchies, both during the day and at night. The social status of dominant birds tended to remain stable but changed continually in subordinate birds. Dominant birds were more loyal than subordinate birds to particular perches within the roost. Roost perch loyalty in dominant birds may be an adaptive behaviour as it ensures familiarity with a perch which has proven to be safe. The role of the communal roost as an 'information-centre' was also investigated in relation to food availability and the social status of the birds. Experiments suggest that individuals- may exploit the communal roost as an 'information-centre' in times of food shortage. Naive birds that were starved tended to follow a dominant knowledgeable roostmate that had been trained to find food by entering another compartment of the aviary via a pipe even when the food source was absent. In contrast, the same naive birds, when they were fed, did not follow the knowledgeable birds. Subordinate and dominant naive birds appeared to be equally likely to follow knowledgeable birds, suggesting that both subordinate and dominant birds could exploit the communal roost as an 'information-centre'.