Energy requirements of Adélie penguin (Pygoscelis adeliae) chicks

The energy requirements of Adélie penguin (Pygoscelis adeliae) chicks were analysed with respect to body mass (W, 0.145-3.35 kg, n = 36) and various forms of activity (lying, standing, minor activity, locomotion, walking on a treadmill). Direct respirometry was used to measure O2 consumption (VO2, l.h-1) and CO2 production. Heart rate (HR, bpm) was recorded from the ECG obtained by both externally attached electrodes and implantable HR-transmitters. The parameters measured were not affected by hand-rearing of the chicks or by implanting transmitters. HR measured in the laboratory and in the field were comparable. Oxygen uptake ranged from VO2 = 1.50.W0.921 in lying chicks to VO2 = 2.25.W1.024 at maximal activity, RQ = 0.76. Metabolic rate in small wild chicks (0.14-0.38 kg) was not affected by time of day, nor was their feeding frequency in the colony (Dec 20-21). Regressions of HR on VO2 were highly significant (p less than 0.0001) in transmitter implanted chicks (n = 4), and two relationships are proposed for the pooled data, one for minor activities (VO2 = -7.23 + 1.82.W + 0.03 HR), and one for walking (VO2 = -11.89 + 1.117.W + 0.058.HR). Oxygen consumption, mass of the chick (2-3 kg), and duration of walking (T, s) were related as VO2 = -0.746 + 1.87.W + 0.076.T, whereas mass-specific O2 consumption was related to walking speed (S, m.s-1) as VO2.W-1 = 1.60 + 7.39.S.