Abstract
Vocalisations (auditory communication) and displays (visual communication) of Bubo bengalensis were recorded in the field over a period of 78 months. This disclosed 18 distinct behavioural traits nine auditory and nine visual. None of these components were solitary units; each led on to another, increasing in intensity and was linked by short duration transition phases. A combination of both auditory and visual displays was found to be the most effective. Three distinct patterns of behaviour were discernable. Their causations, emphasising motivational and phylogenetic elements, are discussed here.