The subjects of this study are nine Humboldt penguins Spheniscus humboldti kept in captivity at the Genoa Aquarium. The ecstatic display is an acoustic behaviour performed both by males and females and its function is not well defined. It was described as an attracting call given by unpaired males toward unattached females or as a territorial display of males. Observations collected over about two years of study have given information about the distribution of this behaviour: males vocalise much more than females and the acoustic activity is higher in the afternoon, when penguins are in or near the nest. The ecstatic display is composed of short initial inspirations, from one to four loud emissions, a final inspiration and, sometimes, a very short emission after last inspiration. Researchers are able to distinguish each individual through its characteristic acoustic patterns ' that enable individual recognition. The following parameters were measured: number of initial inspirations, length of each emission, length of gaps between two emissions, .number of emissions, presence/absence of final inspiration, presence/absence of final short emission, pattern of distribution of dominant frequencies of emissions. Most of these parameters are statistically different between individuals.