African adult penguins communicate using four different vocalizations and juveniles and chicks use two begging calls to request food.
This is according to a study published July 30, 2014 in the open-access journal PLOS ONE
by Livio Favaro and colleagues from University of Turin, Italy.
African penguins vocalize to communicate with their parents, mates, and colony members; however, only basic descriptions of their calls currently exist. To further observe their vocal behavior, the authors of this study collected, categorized, and acoustically analyzed hundreds of audio and video vocal recordings from a large captive colony of penguins in Italy. In addition, they identified the behavioral contexts in which calls were made.
Results show that four basic vocalizations can be found in the auditory repertoire of the adult African penguin: a contact call emitted by isolated birds, an agonistic call used in aggressive interactions, an ecstatic display song uttered by single birds during the breeding season, and a mutual display song vocalized by pairs at their nests. The authors also identified two distinct vocalizations interpreted as begging calls by nesting chicks (begging peep) and unweaned juveniles (begging moan). Since the colony is captive, the authors can't be sure they've identified all possible vocalizations, but they suggest this analysis helps to standardize known vocalizations that can be used in further study of these endangered seabirds.