Use of the Nest Site as a Rendezvous in Penguins

Abstract

For most birds, it is difficult to study what life would be like without nest sites. In penguins, however, nesting and non-nesting species can be compared. We contrasted the King Penguin (Aptenodytes patagonicus), which has no nest and carries its chick on its feet, with the Macaroni Penguin (Eudyptes chrysolophus), which has a nest similar to other birds. We investigated the use of the nest site when it ceased to be necessary, that is, after chick emancipation during the crèche period. When adults return to their crowded colony from foraging at sea, both penguin species exhibit individual recognition between parents and chicks via calls. Observations were made on how parents find and feed large chicks. We examined whether the use of the empty nest as a geographical meeting place was advantageous to Macaroni Penguin parents looking for their chicks, and whether the more sophisticated recognition of calls aided King Penguin parents in searching for their chicks. Macaroni Penguin parents found their chicks in about half a minute, giving two or three calls to bring chicks to the site of their previous nest. In contrast, King Penguin parents took longer (about three minutes) to find their chicks, and gave four or five calls to attract chicks. In addition, about a quarter of King Penguin parents had to walk an average of 11-12 m through the crèche in order to find a chick to feed. For Macaroni chicks and their parents, the nest was used as a “rendezvous” location that facilitated reunion.