Dataset for <i>Foraging flexibility in response to at-sea constraints in a deep diver, the king penguin: an experimental study</i>

35 pairs of breeding king peguins were monitored in two different breeding seasons (2019 N = 14 and 2022 N = 21) and included in an experimental study aiming at increasing the swimming workload at sea. Pairs were included in two different groups (Control, N = 18 and Treated N = 17), Treated birds were fitted with an additionnal dummy logger during two consecutive foraging trips during chick-brooding. We evaluated the effect of the treatment on the foraging behavior at sea of adults and the growth and Survival of their chicks.