The adaptation of individual information transfer in a colonial environment. The case of penguins

Individual recognition by voice in colonial birds has to face the acoustic properties of the colonial environment, which is a medium difficult to penetrate, and where sound propagation appears random. We examined two parameters of the communication system in penguins, in relation to the degree of coloniality of the species: first the signalling posture, with the beak directed upwards in all species except for Emperor penguins that outstandingly directs its beak downwards; second the structure of the identification signal, characterized by a beat phenomenon in Emperor and King penguins. Within the context of the search for the partner or the chick, it appeared that signalling posture and sound structure were all the more sophisticated that the sound transmission was difficul