Context-dependent 'safekeeping' of foraging tools in New Caledonian crows

Barbara Christina Klump, Jessica Eva Megan van der Wal, James St Clair, Christian Rutz

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)
1 Downloads (Pure)

Abstract

Several animal species use tools for foraging, such as sticks to extract
embedded arthropods and honey, or stones to crack open nuts and eggs.
While providing access to nutritious foods, these behaviours may incur significant costs, such as the time and energy spent searching for, manufacturing and transporting tools. These costs can be reduced by re-using tools, keeping them safe when not needed. We experimentally investigated what New Caledonian crows do with their tools between successive prey extractions, and whether they express tool ‘safekeeping’ behaviours more often when the costs (foraging at height), or likelihood (handling of demanding prey), of toolloss are high. Birds generally took care of their tools (84% of 176 prey extractions, nine subjects), either trapping them underfoot (74%) or storing them in holes (26%)—behaviours we also observed in the wild (19 cases, four subjects). Moreover, tool-handling behaviour was context-dependent, with subjects: keeping their tools safe significantly more often when foraging at height; and storing tools significantly more often in holes when extracting more demanding prey (under these conditions, foot-trapping proved challenging). In arboreal environments, safekeeping can prevent costly tool losses, removing a potentially
important constraint on the evolution of habitual and complex tool behaviour.
Original languageEnglish
Article number20150278
Number of pages8
JournalProceedings of the Royal Society B: Biological Sciences
Volume282
DOIs
Publication statusPublished - 20 May 2015

Keywords

  • Corvid
  • Corvus moneduliodes
  • Material culture
  • Optimal foraging
  • Tool transportation
  • Tool use

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