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Predictability of food supply modulates nocturnal hypothermia in a small passerine : Food supply and nocturnal hypothermia

Nilsson, Johan LU orcid ; Nilsson, Jan-Åke LU ; Broggi, Juli LU and Watson, Hannah LU orcid (2020) In Biology letters 16(6).
Abstract
The combination of short days and long cold winter nights, in temperate regions, presents a major challenge for small diurnal birds. Small birds regularly employ heterothermy and enter rest-phase hypothermia during winter nights to conserve energy. However, we know little about how environmental conditions, such as food availability, shape these strategies. We experimentally manipulated food availability in winter to free-living great tits Parus major. A 'predictable' and constant food supply was provided to birds in one area of a forest, while birds in another area did not have access to a reliable supplementary food source. We found that predictability of food affected the extent of nocturnal hypothermia, but the response differed... (More)
The combination of short days and long cold winter nights, in temperate regions, presents a major challenge for small diurnal birds. Small birds regularly employ heterothermy and enter rest-phase hypothermia during winter nights to conserve energy. However, we know little about how environmental conditions, such as food availability, shape these strategies. We experimentally manipulated food availability in winter to free-living great tits Parus major. A 'predictable' and constant food supply was provided to birds in one area of a forest, while birds in another area did not have access to a reliable supplementary food source. We found that predictability of food affected the extent of nocturnal hypothermia, but the response differed between the sexes. Whereas male nocturnal body temperature was similar regardless of food availability, females exposed to a naturally 'unpredictable' food supply entered deeper hypothermia at night, compared with females that had access to predictable food and compared with males in both treatment groups. We suggest that this response is likely a consequence of dominance, and subdominant females subject to unpredictable food resources cannot maintain sufficient energy intake, resulting in a higher demand for energy conservation at night. (Less)
Please use this url to cite or link to this publication:
author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biology letters
volume
16
issue
6
article number
20200133
pages
4 pages
publisher
Royal Society Publishing
external identifiers
  • pmid:32486941
  • scopus:85085854641
ISSN
1744-957X
DOI
10.1098/rsbl.2020.0133
project
Winter food supply and avian energetics
language
English
LU publication?
yes
id
1bc3e0dd-5472-481a-b66f-67cae43120d5
date added to LUP
2020-10-07 12:18:20
date last changed
2025-09-26 04:01:35
@article{1bc3e0dd-5472-481a-b66f-67cae43120d5,
  abstract     = {{The combination of short days and long cold winter nights, in temperate regions, presents a major challenge for small diurnal birds. Small birds regularly employ heterothermy and enter rest-phase hypothermia during winter nights to conserve energy. However, we know little about how environmental conditions, such as food availability, shape these strategies. We experimentally manipulated food availability in winter to free-living great tits Parus major. A 'predictable' and constant food supply was provided to birds in one area of a forest, while birds in another area did not have access to a reliable supplementary food source. We found that predictability of food affected the extent of nocturnal hypothermia, but the response differed between the sexes. Whereas male nocturnal body temperature was similar regardless of food availability, females exposed to a naturally 'unpredictable' food supply entered deeper hypothermia at night, compared with females that had access to predictable food and compared with males in both treatment groups. We suggest that this response is likely a consequence of dominance, and subdominant females subject to unpredictable food resources cannot maintain sufficient energy intake, resulting in a higher demand for energy conservation at night.}},
  author       = {{Nilsson, Johan and Nilsson, Jan-Åke and Broggi, Juli and Watson, Hannah}},
  issn         = {{1744-957X}},
  language     = {{eng}},
  month        = {{06}},
  number       = {{6}},
  publisher    = {{Royal Society Publishing}},
  series       = {{Biology letters}},
  title        = {{Predictability of food supply modulates nocturnal hypothermia in a small passerine : Food supply and nocturnal hypothermia}},
  url          = {{https://lup.lub.lu.se/search/files/84687216/rsbl.2020.0133.pdf}},
  doi          = {{10.1098/rsbl.2020.0133}},
  volume       = {{16}},
  year         = {{2020}},
}