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Adaptive temperature regulation in the little bird in winter: predictions from a stochastic dynamic programming model

Several species of small birds are resident in boreal forests where environmental temperatures can be −20 to −30 °C, or even lower, in winter. As winter days are short, and food is scarce, winter survival is a challenge for small endothermic animals. A bird of this size will have to gain almost 10%...

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Autores principales: Brodin, Anders, Nilsson, Jan-Åke, Nord, Andreas
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Berlin Heidelberg 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5596050/
https://www.ncbi.nlm.nih.gov/pubmed/28776203
http://dx.doi.org/10.1007/s00442-017-3923-3
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author Brodin, Anders
Nilsson, Jan-Åke
Nord, Andreas
author_facet Brodin, Anders
Nilsson, Jan-Åke
Nord, Andreas
author_sort Brodin, Anders
collection PubMed
description Several species of small birds are resident in boreal forests where environmental temperatures can be −20 to −30 °C, or even lower, in winter. As winter days are short, and food is scarce, winter survival is a challenge for small endothermic animals. A bird of this size will have to gain almost 10% of its lean body mass in fat every day to sustain overnight metabolism. Birds such as parids (titmice and chickadees) can use facultative hypothermia, a process in which body temperature is actively down-regulated to a specific level, to reduce heat loss and thus save energy. During cold winter nights, these birds may decrease body temperature from the normal from 42 ° down to 35 °C, or even lower in some species. However, birds are unable to move in this deep hypothermic state, making it a risky strategy if predators are around. Why, then, do small northern birds enter a potentially dangerous physiological state for a relatively small reduction in energy expenditure? We used stochastic dynamic programming to investigate this. Our model suggests that the use of nocturnal hypothermia at night is paramount in these biomes, as it would increase winter survival for a small northern bird by 58% over a winter of 100 days. Our model also explains the phenomenon known as winter fattening, and its relationship to thermoregulation, in northern birds. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00442-017-3923-3) contains supplementary material, which is available to authorized users.
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spelling pubmed-55960502017-10-02 Adaptive temperature regulation in the little bird in winter: predictions from a stochastic dynamic programming model Brodin, Anders Nilsson, Jan-Åke Nord, Andreas Oecologia Behavioral Ecology–Original Research Several species of small birds are resident in boreal forests where environmental temperatures can be −20 to −30 °C, or even lower, in winter. As winter days are short, and food is scarce, winter survival is a challenge for small endothermic animals. A bird of this size will have to gain almost 10% of its lean body mass in fat every day to sustain overnight metabolism. Birds such as parids (titmice and chickadees) can use facultative hypothermia, a process in which body temperature is actively down-regulated to a specific level, to reduce heat loss and thus save energy. During cold winter nights, these birds may decrease body temperature from the normal from 42 ° down to 35 °C, or even lower in some species. However, birds are unable to move in this deep hypothermic state, making it a risky strategy if predators are around. Why, then, do small northern birds enter a potentially dangerous physiological state for a relatively small reduction in energy expenditure? We used stochastic dynamic programming to investigate this. Our model suggests that the use of nocturnal hypothermia at night is paramount in these biomes, as it would increase winter survival for a small northern bird by 58% over a winter of 100 days. Our model also explains the phenomenon known as winter fattening, and its relationship to thermoregulation, in northern birds. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00442-017-3923-3) contains supplementary material, which is available to authorized users. Springer Berlin Heidelberg 2017-08-03 2017 /pmc/articles/PMC5596050/ /pubmed/28776203 http://dx.doi.org/10.1007/s00442-017-3923-3 Text en © The Author(s) 2017 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Behavioral Ecology–Original Research
Brodin, Anders
Nilsson, Jan-Åke
Nord, Andreas
Adaptive temperature regulation in the little bird in winter: predictions from a stochastic dynamic programming model
title Adaptive temperature regulation in the little bird in winter: predictions from a stochastic dynamic programming model
title_full Adaptive temperature regulation in the little bird in winter: predictions from a stochastic dynamic programming model
title_fullStr Adaptive temperature regulation in the little bird in winter: predictions from a stochastic dynamic programming model
title_full_unstemmed Adaptive temperature regulation in the little bird in winter: predictions from a stochastic dynamic programming model
title_short Adaptive temperature regulation in the little bird in winter: predictions from a stochastic dynamic programming model
title_sort adaptive temperature regulation in the little bird in winter: predictions from a stochastic dynamic programming model
topic Behavioral Ecology–Original Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5596050/
https://www.ncbi.nlm.nih.gov/pubmed/28776203
http://dx.doi.org/10.1007/s00442-017-3923-3
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