Energy requirements of Pygoscelid penguins: a synopsis

Based on the results obtained during 3 Antarctic expeditions, which have been published or submitted in 31 manuscripts since 1989, I compiled in this synopsis the energy and food requirements of Adelie (Pygoscelis adeliae), Chinstrap (P. antarctica) and Gentoo (P. papua) penguins during the breeding season. For that purpose, I used data on microclimate, bird activity on land, the usage of fat reserves, and data on the energetic costs associated with swimming and resting in cold water (4 C). The different data as well as the results of the model were cross-checked with published data or results obtained through other experimental methods, i.e. hydrodynamic investigations on plastic-cast models in a circulating water tank or studies on live penguins using doubly-labelled water. Resting metabolic rate (RMR) of Adelie penguins on land concurred with data published in the literature. Although RMR of penguins in cold water was significantly lower than published values, calculation of penguin heat loss using these figures was matched by the results of Kooyman et al. (1976) who determined heat conductivity in penguin pelts. Similarly, cost of transport in penguins swimming under-water was significantly lower than published values for other penguin species. However my results were matched by those of a study on hydrodynamic properties of plastic-cast penguin models. Finally, calculations of the field metabolic rates of Adelie penguins using respirometry data and time-activity budgets doubly-labelled water study. (orig.)Printed version of a habilitation thesis submitted to and accepted by Mathematisch-Naturwisschenschaftliche Fakultaet of the University of Kiel. Orig.: Energy requirements of Pygoscelid penguins. Pt. 1: synopsisAvailable from TIB Hannover: RN 9219(150) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Surviving probability indicators of landing juvenile magellanic penguins arriving along the southern brazilian coast

The aim of this work was to monitor and study the hematocrit and weight of juvenile penguins, with and without oil cover, found alive along the southern coast of Brazil, after capture, as well as before eventual death or release Released juvenile penguins showed higher weight and hematocrit (3.65 ± 0.06 kg and 44.63 ± 0.29%, respectively) than those that died (2.88 ± 0.08 kg and 34.42 ± 1.70%, respectively). Penguins with higher hematocrit and weigh after capture had higher mean weight gain than their counterparts with smaller hematocrit and weight after the capture. Besides, juveniles with higher hematocrit and weight after the capture had higher survival rates, independent of the presence or absence of oil. The results suggested that juveniles covered with oil might have been healthier than the juveniles without oil. The animals without oil probably died as a consequence of health disturbances, while the animals with oil possibly were healthy before contact with oil in the sea

Thermal substitution and aerobic efficiency: measuring and predicting effects of heat balance on endotherm diving energetics

For diving endotherms, modelling costs of locomotion as a function of prey dispersion requires estimates of the costs of diving to different depths. One approach is to estimate the physical costs of locomotion (Pmech) with biomechanical models and to convert those estimates to chemical energy needs by an aerobic efficiency (η=Pmech/Vo2) based on oxygen consumption (Vo2) in captive animals. Variations in η with temperature depend partly on thermal substitution, whereby heat from the inefficiency of exercising muscles or the heat increment of feeding (HIF) can substitute for thermogenesis. However, measurements of substitution have ranged from lack of detection to nearly complete use of exercise heat or HIF. This inconsistency may reflect (i) problems in methods of calculating substitution, (ii) confounding mechanisms of thermoregulatory control, or (iii) varying conditions that affect heat balance and allow substitution to be expressed. At present, understanding of how heat generation is regulated, and how heat is transported among tissues during exercise, digestion, thermal challenge and breath holding, is inadequate for predicting substitution and aerobic efficiencies without direct measurements for conditions of interest. Confirming that work rates during exercise are generally conserved, and identifying temperatures at those work rates below which shivering begins, may allow better prediction of aerobic efficiencies for ecological models