Individual differences in searching behaviour and spatial foraging consistency in a central place marine predator

Samantha C. Patrick*, Stuart Bearhop, David Gremillet, Amelie Lescroel, W. James Grecian, Thomas W. Bodey, Keith C. Hamer, Ewan Wakefield, Melanie Le Nuz, Stephen C. Votier

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

98 Citations (Scopus)

Abstract

Consistent intra-population variability in foraging behaviour is found among a wide range of taxa. Such foraging specialisations are common among marine vertebrates, yet it is not clear how individuals repeatedly locate prey or foraging sites at ocean-wide scales. Using GPS and time-depth loggers we studied the fine-scale foraging behaviour of central-place northern gannets Morus bassanus at two large colonies. First, we estimated the degree of consistency in individual foraging routes and sites across repeated trips. Second, we tested for individual differences in searching behaviour in response to environmental covariates using reaction norms, estimated from mixed effect models. Adult gannets tracked over multiple foraging trips showed repeatable between-individual differences in terminal points and departure angles of foraging trips, but low repeatability in trip duration and trip length. Importantly, individual birds showed highly repeatable dive locations, with consistently different environmental conditions (such as copepod abundance), suggesting a high degree of foraging site specialisation. Gannets also showed between-individual differences in searching behaviour along environmental gradients, such that individuals intensified searching under different conditions. Together these results suggest that widespread individual foraging consistency may represent specialisation and be linked with individual responses to environmental conditions. Such divergent searching behaviour could provide a mechanism by which consistent foraging behaviour arises and is maintained among animals that forage across large spatial scales.

Original languageEnglish
Pages (from-to)33-40
Number of pages8
JournalOikos
Volume123
Issue number1
Early online date27 Aug 2013
DOIs
Publication statusPublished - Jan 2014

Keywords

  • NORTHERN GANNETS
  • WANDERING ALBATROSS
  • PHENOTYPIC PLASTICITY
  • SEXUAL-DIMORPHISM
  • DIOMEDEA-EXULANS
  • STABLE-ISOTOPES
  • FINE-SCALE
  • SEABIRDS
  • PREY
  • SEA

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