What parameters can be used for individual acoustic recognition by the greater flamingo?

The greater flamingo Phoenicopterus ruber is a colonial bird for which acoustic communication plays a great role, in particular during the mating period. The study of contact calls emitted by the adults allow enables identification of some acoustic parameters which may be used for individual recognition. It appears that the frequential values of the harmonics, the distribution of energy in the spectrum as well as beats (mimicking amplitude modulations) are susceptible to represent individual markers. On the contrary, the coding of the individual identity does not depend on frequency modulation since this latter is practically lacking. These results are remarkably similar to those obtained from another colonial bird species, the emperor penguin Aptenodytes forsteri, and may correspond to signal adaptations to special acoustic constraints of the colonial way of life.