LAMBERTUCCI Sergio Agustin
congresos y reuniones científicas
In-flight energy gains reveal benefits of being big: the case of the Andean Condor.
Congreso; British Ornithological Union Annual Conference; 2015
The cost of transport concept assumes that energy is only ever lost as animals move. This may be true in a physiological sense, but animals can gain kinetic energy from currents or potential energy from updraughts. Both are valuable and many species are known to modulate their movements with respect to these sources of ?free energy?. This study proposes that the different forms of energy (metabolic power use and environmental energy gain) can be treated as power terms and combined to give an estimate of ?total system power?. This is illustrated using high-resolution movement data from Andean Condors Vultur gryphus recorded using Daily Diary units. Estimates of metabolic power use were derived from measurements of body acceleration, which were combined with rates of power gain or loss associated with changes in altitude (i.e. potential energy). Both parameters were linked to GPS location, which was sampled every 1 or 2 minutes. The results represent the first estimates of the non-biochemical energy contribution to movement costs in wild animals. Values of total system power show that Condors and other soaring birds can accrue energy from the environment at a greater rate than they spend it during soaring flight, even accepting the limitations of the model approach. This is a consequence of the low mass-specific metabolic rates of larger birds, which can therefore be considered an adaptation, maximising the relative value of environmental energy. Nonetheless, in Condors, spatial patterns in power gain and use suggest that, while profitable flight conditions exist across habitat types (the forested Andes and the arid steppe), high flight costs are associated with the assessment of potential feeding locations. This illustrates the importance of selecting landing sites and the mitigation of costs and/ or risks associated with take-off. Overall, the energy gains available in the environment and their spatiotemporal distribution have important implications for animal ecology and the understanding of energy budgets.