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Mass-dependent predation and metabolic expenditure in wintering birds: is there a trade-off between different forms of predation?

Brodin, Anders LU (2001) In Animal Behaviour 62(5). p.993-999
Abstract
Passerines maintain low levels of fat in winter even though larger fat reserves would provide better insurance against starvation. This is believed to be a result of predation risk and/or metabolic expenditure increasing with the amount of fat carried. Recent empirical studies indicate that the effect of increased mass on predation risk is small, but the effect on metabolic expenditure is large. Using dynamic modelling, I investigated how mass-dependent costs affect the pattern of fat gain. I found that increases in metabolic expenditure were sufficient to explain strong regulation of the level of fat, but that increases in direct predation risk cannot be excluded. A plausible explanation for the increase in metabolic expenditure is if the... (More)
Passerines maintain low levels of fat in winter even though larger fat reserves would provide better insurance against starvation. This is believed to be a result of predation risk and/or metabolic expenditure increasing with the amount of fat carried. Recent empirical studies indicate that the effect of increased mass on predation risk is small, but the effect on metabolic expenditure is large. Using dynamic modelling, I investigated how mass-dependent costs affect the pattern of fat gain. I found that increases in metabolic expenditure were sufficient to explain strong regulation of the level of fat, but that increases in direct predation risk cannot be excluded. A plausible explanation for the increase in metabolic expenditure is if the extra weight is compensated for by a parallel gain in flight muscle. Such compensation means that an increase in instantaneous predation risk can be avoided, but that costs depending on an increase in energy intake may occur instead. For example more time spent foraging increases exposure to predators, Hence, one form of predation risk (impaired ability to escape from an attacking predator) may be traded for another (more time spent foraging). This will be beneficial if this extended foraging is not risky, whereas failure to compensate for the extra mass would mean the risk of being caught by a predator increasing considerably. Besides the widely recognized trade-off between starvation and predation, this means that there may also be a trade-off between different forms of predation in wintering birds. (C) 2001 The Association for the Study of Animal Behaviour. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Animal Behaviour
volume
62
issue
5
pages
993 - 999
publisher
Elsevier Ltd
external identifiers
  • scopus:0035662599
ISSN
1095-8282
DOI
10.1006/anbe.2001.1844
language
English
LU publication?
yes
id
4a907847-3338-471f-a8f0-6314f44cd824 (old id 147467)
date added to LUP
2007-07-03 11:06:53
date last changed
2018-04-08 03:35:05
@article{4a907847-3338-471f-a8f0-6314f44cd824,
  abstract     = {Passerines maintain low levels of fat in winter even though larger fat reserves would provide better insurance against starvation. This is believed to be a result of predation risk and/or metabolic expenditure increasing with the amount of fat carried. Recent empirical studies indicate that the effect of increased mass on predation risk is small, but the effect on metabolic expenditure is large. Using dynamic modelling, I investigated how mass-dependent costs affect the pattern of fat gain. I found that increases in metabolic expenditure were sufficient to explain strong regulation of the level of fat, but that increases in direct predation risk cannot be excluded. A plausible explanation for the increase in metabolic expenditure is if the extra weight is compensated for by a parallel gain in flight muscle. Such compensation means that an increase in instantaneous predation risk can be avoided, but that costs depending on an increase in energy intake may occur instead. For example more time spent foraging increases exposure to predators, Hence, one form of predation risk (impaired ability to escape from an attacking predator) may be traded for another (more time spent foraging). This will be beneficial if this extended foraging is not risky, whereas failure to compensate for the extra mass would mean the risk of being caught by a predator increasing considerably. Besides the widely recognized trade-off between starvation and predation, this means that there may also be a trade-off between different forms of predation in wintering birds. (C) 2001 The Association for the Study of Animal Behaviour.},
  author       = {Brodin, Anders},
  issn         = {1095-8282},
  language     = {eng},
  number       = {5},
  pages        = {993--999},
  publisher    = {Elsevier Ltd},
  series       = {Animal Behaviour},
  title        = {Mass-dependent predation and metabolic expenditure in wintering birds: is there a trade-off between different forms of predation?},
  url          = {http://dx.doi.org/10.1006/anbe.2001.1844},
  volume       = {62},
  year         = {2001},
}