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Age-dependent effects of predation risk on night-time hypothermia in two wintering passerine species

Andreasson, Fredrik LU ; Nord, Andreas LU and Nilsson, Jan Åke LU (2019) In Oecologia
Abstract

Small animals that winter at northern latitudes need to maximize energy intake and minimize energy loss. Many passerine birds use night-time hypothermia to conserve energy. A potential cost of night-time hypothermia with much theoretical (but little empirical) support is increased risk of night-time predation, due to reduced vigilance and lower escape speed in hypothermic birds. This idea has never been tested in the wild. We, therefore, increased perceived predation risk in great tits (Parus major) and blue tits (Cyanistes caeruleus) roosting in nest boxes during cold winter nights to measure any resultant effect on their use of night-time hypothermia. Roosting birds of both species that experienced their first winter were less prone... (More)

Small animals that winter at northern latitudes need to maximize energy intake and minimize energy loss. Many passerine birds use night-time hypothermia to conserve energy. A potential cost of night-time hypothermia with much theoretical (but little empirical) support is increased risk of night-time predation, due to reduced vigilance and lower escape speed in hypothermic birds. This idea has never been tested in the wild. We, therefore, increased perceived predation risk in great tits (Parus major) and blue tits (Cyanistes caeruleus) roosting in nest boxes during cold winter nights to measure any resultant effect on their use of night-time hypothermia. Roosting birds of both species that experienced their first winter were less prone to use hypothermia as an energy-saving strategy at low ambient temperatures when exposed to increased perceived predation risk either via handling (great tits) or via predator scent manipulation (blue tits). However, we did not record such effects in birds that were in their second winter or beyond. Our results suggest that effects of increased predation risk are age- and temperature specific. This could be caused by age-related differences in experience and subsequent risk assessment, or by dominance-related variation in habitat quality between young and old birds. Predation risk could, through its effect on use and depth of night-time hypothermia, be important for total energy management and winter survival for resident birds at northern latitudes.

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organization
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type
Contribution to journal
publication status
epub
subject
keywords
Cyanistes caeruleus, Heterothermy, Parus major, Predation, Thermoregulation
in
Oecologia
publisher
Springer
external identifiers
  • scopus:85059605729
ISSN
0029-8549
DOI
10.1007/s00442-018-04331-7
language
English
LU publication?
yes
id
9eaed860-78ee-4697-ac91-06a115049557
date added to LUP
2019-01-21 14:01:31
date last changed
2019-04-23 03:00:24
@article{9eaed860-78ee-4697-ac91-06a115049557,
  abstract     = {<p>Small animals that winter at northern latitudes need to maximize energy intake and minimize energy loss. Many passerine birds use night-time hypothermia to conserve energy. A potential cost of night-time hypothermia with much theoretical (but little empirical) support is increased risk of night-time predation, due to reduced vigilance and lower escape speed in hypothermic birds. This idea has never been tested in the wild. We, therefore, increased perceived predation risk in great tits (Parus major) and blue tits (Cyanistes caeruleus) roosting in nest boxes during cold winter nights to measure any resultant effect on their use of night-time hypothermia. Roosting birds of both species that experienced their first winter were less prone to use hypothermia as an energy-saving strategy at low ambient temperatures when exposed to increased perceived predation risk either via handling (great tits) or via predator scent manipulation (blue tits). However, we did not record such effects in birds that were in their second winter or beyond. Our results suggest that effects of increased predation risk are age- and temperature specific. This could be caused by age-related differences in experience and subsequent risk assessment, or by dominance-related variation in habitat quality between young and old birds. Predation risk could, through its effect on use and depth of night-time hypothermia, be important for total energy management and winter survival for resident birds at northern latitudes.</p>},
  author       = {Andreasson, Fredrik and Nord, Andreas and Nilsson, Jan Åke},
  issn         = {0029-8549},
  keyword      = {Cyanistes caeruleus,Heterothermy,Parus major,Predation,Thermoregulation},
  language     = {eng},
  month        = {01},
  publisher    = {Springer},
  series       = {Oecologia},
  title        = {Age-dependent effects of predation risk on night-time hypothermia in two wintering passerine species},
  url          = {http://dx.doi.org/10.1007/s00442-018-04331-7},
  year         = {2019},
}