Inter-individual communication of large-billed crows: hearing, seeing, and touching

Abstract

Large-billed crows, Corvus macrorhynchos, are one of familiar resident birds in Japan. They are originally jungle/forest-dwelling birds but now broaden their habitats to urban 'concrete jungle' environments such as Tokyo and Sapporo. Despite the close and overlapping range of the habitat between humans and crows, the socio-behavioural function of crows and its psychological and neural underpinnings have been poorly understood. Here, I review the recent studies in animal psychology on inter-individual communication for the understanding of individual-based social ecology of large-billed crows. Particular focuses are made on audio-vocal, visual, and tactile communication. First, vocal exchange with a contact call (ka call) and the acoustic individuality of ka calls as an identity signal are outlined. Second topic for visual communication is on audio-visual cross-modal recognition of familiar individuals and the involvement of the individual recognition in the formation and maintenance of dominance relationship. Finally, nonreciprocal but unidirectional allopreening from dominants to subordinates in juvenile males is shown and its possible social function are discussed. To further understand the communication of crows from comparative perspectives, these findings of social behaviour and its function should be integrated with physiological research on the... onto the life-history axis of this species which is characterized by drastic change of social structures between juvenile and pair-bond stages.