The function of feeding chases in the chinstrap penguin, Pygoscelis antarctica

Abstract

Crèching chinstrap penguin chicks chase their parents on the run before being fed. This characteristic behaviour of Pygoscelid penguins has been interpreted in several ways. In an observational study of several colonies in a rookery on Deception Island, South Shetlands, the frequency and duration of feeding chases in families with one and two chicks were compared. Significantly more feedings occurred outside the crèche in two-chick than in one-chick families. Chases were significantly more frequent and prolonged in families with two than in those with single chicks. This difference was independent of the number of chicks present in the interactions (one or two siblings in two-chick families). Chases during feedings by single chicks were significantly less frequent and prolonged than those by one chick when its sibling was absent. Siblings chasing more intensively obtained more feedings. There was no increase in chasing effort with chick age. These results suggest that feeding chases allow parents to regulate food distribution between siblings according to their needs or hunger but they could also allow brood reduction in times of food crises