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To graze or gorge : Consistency and flexibility of individual foraging tactics in tits

Milligan, Nicole D.; Radersma, Reinder LU ; Cole, Ella F. and Sheldon, Ben C. (2017) In Journal of Animal Ecology
Abstract

An individual's foraging behaviour and time allocated to feeding have direct consequences for its fitness. Despite much research on population-level foraging decisions, few studies have investigated individual differences in fine-scale daily foraging patterns among wild animals. Here, we explore the consistency and plasticity of feeding tactics of individual great tits (Parus major) and blue tits (Cyanistes caeruleus), using a grid of 65 automated feeding stations in a 385-ha woodland, during three winters. We use a principal component analysis to describe individual variation in six feeding parameters and examine how these differences covary with dominance-linked attributes (species, age and sex), the personality trait 'exploration... (More)

An individual's foraging behaviour and time allocated to feeding have direct consequences for its fitness. Despite much research on population-level foraging decisions, few studies have investigated individual differences in fine-scale daily foraging patterns among wild animals. Here, we explore the consistency and plasticity of feeding tactics of individual great tits (Parus major) and blue tits (Cyanistes caeruleus), using a grid of 65 automated feeding stations in a 385-ha woodland, during three winters. We use a principal component analysis to describe individual variation in six feeding parameters and examine how these differences covary with dominance-linked attributes (species, age and sex), the personality trait 'exploration behaviour', distance to territory and local competition intensity. Analysis of 933 086 feeder visits by 3134 individuals revealed that the majority of variation in the timing of feeding was explained by two principal components. PC1 ('binge-eating'), accounting for 38% of variation, captured temporal clustering of feeding, with high repeatability both within and between years (r range: 0·42-0·55). PC2 ('transience'), accounting for 27% of variance, described how much individuals used feeders and was also repeatable (r: 0·34-0·62). While exhibiting consistent individual differences, birds also showed flexibility in foraging patterns, binge-eating less and using feeders more when they experienced greater local competition. Individuals in behaviourally dominant states (great tits, males and adults) binged more than subordinate birds (blue tits, females and juveniles) when their territories were distant from feeding stations. Moreover, great tits and males used feeders more than blue tits and females respectively, while birds feeding further from their territory used feeders less than those feeding closer. 'Exploration behaviour' was unrelated to both measures of daily foraging behaviour. This study presents some of the first evidence that birds use consistent alternative foraging tactics at a fine temporal scale. Individuals are consistent in their tactics, and also adjust their foraging behaviour with changes in local competition. Hence, studies of foraging behaviour should consider the extent to which such individual-level variability in foraging behaviour is under selection.

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author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
PCA, Competition, Consistent differences, Daily routine, Diel activity, Paridae, Principal component analysis, Repeatability
in
Journal of Animal Ecology
publisher
Federation of European Neuroscience Societies and Blackwell Publishing Ltd
external identifiers
  • scopus:85018239458
  • wos:000403146400012
ISSN
0021-8790
DOI
10.1111/1365-2656.12651
language
English
LU publication?
yes
id
15f9fd53-4bd8-40e8-8046-81f014728caa
date added to LUP
2017-05-23 09:51:25
date last changed
2018-01-07 12:04:46
@article{15f9fd53-4bd8-40e8-8046-81f014728caa,
  abstract     = {<p>An individual's foraging behaviour and time allocated to feeding have direct consequences for its fitness. Despite much research on population-level foraging decisions, few studies have investigated individual differences in fine-scale daily foraging patterns among wild animals. Here, we explore the consistency and plasticity of feeding tactics of individual great tits (Parus major) and blue tits (Cyanistes caeruleus), using a grid of 65 automated feeding stations in a 385-ha woodland, during three winters. We use a principal component analysis to describe individual variation in six feeding parameters and examine how these differences covary with dominance-linked attributes (species, age and sex), the personality trait 'exploration behaviour', distance to territory and local competition intensity. Analysis of 933 086 feeder visits by 3134 individuals revealed that the majority of variation in the timing of feeding was explained by two principal components. PC1 ('binge-eating'), accounting for 38% of variation, captured temporal clustering of feeding, with high repeatability both within and between years (r range: 0·42-0·55). PC2 ('transience'), accounting for 27% of variance, described how much individuals used feeders and was also repeatable (r: 0·34-0·62). While exhibiting consistent individual differences, birds also showed flexibility in foraging patterns, binge-eating less and using feeders more when they experienced greater local competition. Individuals in behaviourally dominant states (great tits, males and adults) binged more than subordinate birds (blue tits, females and juveniles) when their territories were distant from feeding stations. Moreover, great tits and males used feeders more than blue tits and females respectively, while birds feeding further from their territory used feeders less than those feeding closer. 'Exploration behaviour' was unrelated to both measures of daily foraging behaviour. This study presents some of the first evidence that birds use consistent alternative foraging tactics at a fine temporal scale. Individuals are consistent in their tactics, and also adjust their foraging behaviour with changes in local competition. Hence, studies of foraging behaviour should consider the extent to which such individual-level variability in foraging behaviour is under selection.</p>},
  author       = {Milligan, Nicole D. and Radersma, Reinder and Cole, Ella F. and Sheldon, Ben C.},
  issn         = {0021-8790},
  keyword      = {PCA,Competition,Consistent differences,Daily routine,Diel activity,Paridae,Principal component analysis,Repeatability},
  language     = {eng},
  month        = {04},
  publisher    = {Federation of European Neuroscience Societies and Blackwell Publishing Ltd},
  series       = {Journal of Animal Ecology},
  title        = {To graze or gorge : Consistency and flexibility of individual foraging tactics in tits},
  url          = {http://dx.doi.org/10.1111/1365-2656.12651},
  year         = {2017},
}