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Energy reserves, information need and a pinch of personality determine decision-making on route in partially migratory blue tits

Nilsson, Anna L K; Nilsson, Jan Åke LU and Mettke-Hofmann, Claudia (2016) In PLoS ONE 11(10).
Abstract

In facultative partial migrants some individuals in a population are migratory and others are resident and individuals decide each year anew which strategy to choose. While the proportion of birds migrating is in part determined by environmental conditions and competitive abilities, the timing of individual departure and behaviours on route are little understood. Individuals encounter different environmental conditions when migrating earlier or later. Based on cost/ benefit considerations we tested whether behaviours on route were affected by time constraints, personality and/or age in a partially migrating population of Blue tits (Cyanistes caeruleus). We captured female Blue tits on migration at the Southern tip of Sweden during... (More)

In facultative partial migrants some individuals in a population are migratory and others are resident and individuals decide each year anew which strategy to choose. While the proportion of birds migrating is in part determined by environmental conditions and competitive abilities, the timing of individual departure and behaviours on route are little understood. Individuals encounter different environmental conditions when migrating earlier or later. Based on cost/ benefit considerations we tested whether behaviours on route were affected by time constraints, personality and/or age in a partially migrating population of Blue tits (Cyanistes caeruleus). We captured female Blue tits on migration at the Southern tip of Sweden during early, peak and late migration and measured latency to feed in an unfamiliar environment, exploration of a novel object and hesitation to feed beside a novel object (neophobia). Lean birds and birds with long wings started feeding earlier when released into the cage indicating that foraging decisions were mainly determined by energetic needs (lean and large birds). However, juveniles commenced feeding later with progression of the migratory season in concordance with predictions about personality effects. Furthermore, lean birds started to explore earlier than birds with larger fat reserves again indicating an effect of maintaining threshold energy reserves. Moreover, late migrating juveniles, started to explore earlier than early migrating juveniles possibly due to time constraints to find high-quality foraging patches or a suitable winter home. Finally, neophobia did not change over the migratory season indicating that this behaviour is not compromised by time constraints. The results overall indicate that decisions on route are mainly governed by energetic requirements and current needs to learn about the environment and only to a small extent by differences in personality.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
PLoS ONE
volume
11
issue
10
publisher
Public Library of Science
external identifiers
  • scopus:84991210462
  • wos:000385505300013
ISSN
1932-6203
DOI
10.1371/journal.pone.0163213
language
English
LU publication?
yes
id
216bf0c7-946b-4df8-8178-5900d7ed7a30
date added to LUP
2016-11-01 13:37:50
date last changed
2017-05-28 04:53:56
@article{216bf0c7-946b-4df8-8178-5900d7ed7a30,
  abstract     = {<p>In facultative partial migrants some individuals in a population are migratory and others are resident and individuals decide each year anew which strategy to choose. While the proportion of birds migrating is in part determined by environmental conditions and competitive abilities, the timing of individual departure and behaviours on route are little understood. Individuals encounter different environmental conditions when migrating earlier or later. Based on cost/ benefit considerations we tested whether behaviours on route were affected by time constraints, personality and/or age in a partially migrating population of Blue tits (Cyanistes caeruleus). We captured female Blue tits on migration at the Southern tip of Sweden during early, peak and late migration and measured latency to feed in an unfamiliar environment, exploration of a novel object and hesitation to feed beside a novel object (neophobia). Lean birds and birds with long wings started feeding earlier when released into the cage indicating that foraging decisions were mainly determined by energetic needs (lean and large birds). However, juveniles commenced feeding later with progression of the migratory season in concordance with predictions about personality effects. Furthermore, lean birds started to explore earlier than birds with larger fat reserves again indicating an effect of maintaining threshold energy reserves. Moreover, late migrating juveniles, started to explore earlier than early migrating juveniles possibly due to time constraints to find high-quality foraging patches or a suitable winter home. Finally, neophobia did not change over the migratory season indicating that this behaviour is not compromised by time constraints. The results overall indicate that decisions on route are mainly governed by energetic requirements and current needs to learn about the environment and only to a small extent by differences in personality.</p>},
  articleno    = {e0163213},
  author       = {Nilsson, Anna L K and Nilsson, Jan Åke and Mettke-Hofmann, Claudia},
  issn         = {1932-6203},
  language     = {eng},
  month        = {10},
  number       = {10},
  publisher    = {Public Library of Science},
  series       = {PLoS ONE},
  title        = {Energy reserves, information need and a pinch of personality determine decision-making on route in partially migratory blue tits},
  url          = {http://dx.doi.org/10.1371/journal.pone.0163213},
  volume       = {11},
  year         = {2016},
}