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Energy Beyond Food: Foraging Theory Informs Time Spent in Thermals by a Large Soaring Bird

Current understanding of how animals search for and exploit food resources is based on microeconomic models. Although widely used to examine feeding, such constructs should inform other energy-harvesting situations where theoretical assumptions are met. In fact, some animals extract non-food forms o...

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Autores principales: Shepard, Emily L. C., Lambertucci, Sergio A., Vallmitjana, Diego, Wilson, Rory P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3210787/
https://www.ncbi.nlm.nih.gov/pubmed/22087301
http://dx.doi.org/10.1371/journal.pone.0027375
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author Shepard, Emily L. C.
Lambertucci, Sergio A.
Vallmitjana, Diego
Wilson, Rory P.
author_facet Shepard, Emily L. C.
Lambertucci, Sergio A.
Vallmitjana, Diego
Wilson, Rory P.
author_sort Shepard, Emily L. C.
collection PubMed
description Current understanding of how animals search for and exploit food resources is based on microeconomic models. Although widely used to examine feeding, such constructs should inform other energy-harvesting situations where theoretical assumptions are met. In fact, some animals extract non-food forms of energy from the environment, such as birds that soar in updraughts. This study examined whether the gains in potential energy (altitude) followed efficiency-maximising predictions in the world's heaviest soaring bird, the Andean condor (Vultur gryphus). Animal-attached technology was used to record condor flight paths in three-dimensions. Tracks showed that time spent in patchy thermals was broadly consistent with a strategy to maximise the rate of potential energy gain. However, the rate of climb just prior to leaving a thermal increased with thermal strength and exit altitude. This suggests higher rates of energetic gain may not be advantageous where the resulting gain in altitude would lead to a reduction in the ability to search the ground for food. Consequently, soaring behaviour appeared to be modulated by the need to reconcile differing potential energy and food energy distributions. We suggest that foraging constructs may provide insight into the exploitation of non-food energy forms, and that non-food energy distributions may be more important in informing patterns of movement and residency over a range of scales than previously considered.
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spelling pubmed-32107872011-11-15 Energy Beyond Food: Foraging Theory Informs Time Spent in Thermals by a Large Soaring Bird Shepard, Emily L. C. Lambertucci, Sergio A. Vallmitjana, Diego Wilson, Rory P. PLoS One Research Article Current understanding of how animals search for and exploit food resources is based on microeconomic models. Although widely used to examine feeding, such constructs should inform other energy-harvesting situations where theoretical assumptions are met. In fact, some animals extract non-food forms of energy from the environment, such as birds that soar in updraughts. This study examined whether the gains in potential energy (altitude) followed efficiency-maximising predictions in the world's heaviest soaring bird, the Andean condor (Vultur gryphus). Animal-attached technology was used to record condor flight paths in three-dimensions. Tracks showed that time spent in patchy thermals was broadly consistent with a strategy to maximise the rate of potential energy gain. However, the rate of climb just prior to leaving a thermal increased with thermal strength and exit altitude. This suggests higher rates of energetic gain may not be advantageous where the resulting gain in altitude would lead to a reduction in the ability to search the ground for food. Consequently, soaring behaviour appeared to be modulated by the need to reconcile differing potential energy and food energy distributions. We suggest that foraging constructs may provide insight into the exploitation of non-food energy forms, and that non-food energy distributions may be more important in informing patterns of movement and residency over a range of scales than previously considered. Public Library of Science 2011-11-08 /pmc/articles/PMC3210787/ /pubmed/22087301 http://dx.doi.org/10.1371/journal.pone.0027375 Text en Shepard et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Shepard, Emily L. C.
Lambertucci, Sergio A.
Vallmitjana, Diego
Wilson, Rory P.
Energy Beyond Food: Foraging Theory Informs Time Spent in Thermals by a Large Soaring Bird
title Energy Beyond Food: Foraging Theory Informs Time Spent in Thermals by a Large Soaring Bird
title_full Energy Beyond Food: Foraging Theory Informs Time Spent in Thermals by a Large Soaring Bird
title_fullStr Energy Beyond Food: Foraging Theory Informs Time Spent in Thermals by a Large Soaring Bird
title_full_unstemmed Energy Beyond Food: Foraging Theory Informs Time Spent in Thermals by a Large Soaring Bird
title_short Energy Beyond Food: Foraging Theory Informs Time Spent in Thermals by a Large Soaring Bird
title_sort energy beyond food: foraging theory informs time spent in thermals by a large soaring bird
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3210787/
https://www.ncbi.nlm.nih.gov/pubmed/22087301
http://dx.doi.org/10.1371/journal.pone.0027375
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