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Patterns and dynamics of rest-phase hypothermia in wild and captive blue tits during winter.

Nord, Andreas LU ; Nilsson, Johan LU ; Sandell, Maria LU and Nilsson, Jan-Åke LU (2009) In Journal of Comparative Physiology B 179. p.737-745
Abstract
We evaluated biotic and abiotic predictors of rest-phase hypothermia in wintering blue tits (Cyanistes caeruleus) and also assessed how food availability influences nightly thermoregulation. On any given night, captive blue tits (with unrestricted access to food) remained largely homeothermic, whereas free-ranging birds decreased their body temperature (T (b)) by about 5 degrees C. This was not an effect of increased stress in the aviary as we found no difference in circulating corticosterone between groups. Nocturnal T (b) in free-ranging birds varied with ambient temperature, date and time. Conversely, T (b) in captive birds could not be explained by climatic or temporal factors, but differed slightly between the sexes. We argue that the... (More)
We evaluated biotic and abiotic predictors of rest-phase hypothermia in wintering blue tits (Cyanistes caeruleus) and also assessed how food availability influences nightly thermoregulation. On any given night, captive blue tits (with unrestricted access to food) remained largely homeothermic, whereas free-ranging birds decreased their body temperature (T (b)) by about 5 degrees C. This was not an effect of increased stress in the aviary as we found no difference in circulating corticosterone between groups. Nocturnal T (b) in free-ranging birds varied with ambient temperature, date and time. Conversely, T (b) in captive birds could not be explained by climatic or temporal factors, but differed slightly between the sexes. We argue that the degree of hypothermia is controlled predominantly by birds' ability to obtain sufficient energy reserves during the day. However, environmental factors became increasingly important for thermoregulation when resources were limited. Moreover, as birds did not enter hypothermia in captivity when food was abundant, we suggest that this strategy has associated costs and hence is avoided whenever resource levels permit. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Comparative Physiology B
volume
179
pages
737 - 745
publisher
Springer
external identifiers
  • wos:000268312100008
  • scopus:70349773844
ISSN
0174-1578
DOI
10.1007/s00360-009-0357-1
project
CAnMove
language
English
LU publication?
yes
id
06db743c-a67f-491b-8812-4b8760f5458e (old id 1392311)
date added to LUP
2009-05-12 09:24:46
date last changed
2017-11-19 03:37:13
@article{06db743c-a67f-491b-8812-4b8760f5458e,
  abstract     = {We evaluated biotic and abiotic predictors of rest-phase hypothermia in wintering blue tits (Cyanistes caeruleus) and also assessed how food availability influences nightly thermoregulation. On any given night, captive blue tits (with unrestricted access to food) remained largely homeothermic, whereas free-ranging birds decreased their body temperature (T (b)) by about 5 degrees C. This was not an effect of increased stress in the aviary as we found no difference in circulating corticosterone between groups. Nocturnal T (b) in free-ranging birds varied with ambient temperature, date and time. Conversely, T (b) in captive birds could not be explained by climatic or temporal factors, but differed slightly between the sexes. We argue that the degree of hypothermia is controlled predominantly by birds' ability to obtain sufficient energy reserves during the day. However, environmental factors became increasingly important for thermoregulation when resources were limited. Moreover, as birds did not enter hypothermia in captivity when food was abundant, we suggest that this strategy has associated costs and hence is avoided whenever resource levels permit.},
  author       = {Nord, Andreas and Nilsson, Johan and Sandell, Maria and Nilsson, Jan-Åke},
  issn         = {0174-1578},
  language     = {eng},
  pages        = {737--745},
  publisher    = {Springer},
  series       = {Journal of Comparative Physiology B},
  title        = {Patterns and dynamics of rest-phase hypothermia in wild and captive blue tits during winter.},
  url          = {http://dx.doi.org/10.1007/s00360-009-0357-1},
  volume       = {179},
  year         = {2009},
}