The available literature on the Google talks about two interesting behaviour of Indian Grey Hornbills namely Aerial Jousting and Bill Grappling. These two have been interpreted either as aggression ,social interactions, pair bonding or play.
Dr Raju Kasambe with Bombay Natural History Society, Mumbai and Sh Pravin Charde have suggested that the bill grappling and aerial jousting may be explained in two different context of the life cycles. Social play in the non-breeding time and as a courtship ritual in the adult during the breeding birds.