The food and energy intake rates of adult emperor penguins (Aptenodytes forsteri) rearing chicks

Abstract

The food and energy requirements of adult emperor penguins parenting chicks were examined at Auster (about 11 000 pairs) and Taylor Glacier (about 2900 pairs) colonies during the winter, spring and summer of 1988. Tritiated water-derived estimates of food consumption trebled during the five-month period of chick care, ranging from 2.3 kg d⁻¹ in winter when chicks were <5% of adult mass, to 6.3 kg d⁻¹ in summer, when chicks represented 40–50% of adult mass. These food consumption rates were equivalent to the acquisition of 11.4 MJ d⁻¹ and 33.4 MJ d⁻¹ metabolizable energy in winter and summer respectively. Chick provisioning was not accompanied by a major increase in food consumption by adults. Adults assimilated 84–92% of their daily food intake themselves and retained the remainder for the chick. The food ration of chick for the three seasons (42 kg) constituted only about 9.5% of adult maintenance requirements during the same period. Adults consumed an estimated 482 kg of food (including the ration for the chick), which amounted to about 10 700 t and 2800 t of fish and squid consumed by the breeding populations at Auster and Taylor Glacier, respectively.