This paper examines the foraging behaviour of Adélie penguin parents and the provisioning of their chicks during the guard and crèche stages of chick development. The differences, observed in three poor breeding seasons compared with six seasons where a higher fledging success was achieved, are highlighted. A continuous collection of data on foraging trip duration and meal mass (arrival weight minus departure weight) from birds of known breeding status and sex was obtained using an automated monitoring system. It is concluded that chicks during the guard stage are most vulnerable to a decreased availability of food and thus most susceptible to competition from a fishery.