Ground-hornbills (Bucorvus) show means-end understanding in a horizontal two-string discrimination task
This study investigates problem solving in one northern ground hornbill (Bucorvus abyssinicus) and two southern ground-hornbills (Bucorvus leadbeateri) in a horizontal string-pulling task. In five conditions, two strings were stretched out on the ground and subjects had to pull the end of the string which was properly connected to an out-of-reach food reward. Two subjects succeeded above chance in choosing a rewarded string over an unrewarded one (parallel and converged conditions), and continued pulling longer strings when the reward did not immediately move closer (coiled condition). One bird additionally understood which string was physically connected to the reward (contact condition). Although this study is preliminary, it highlights the necessity to extend research on physical cognition to other large-brained avian orders in order to better understand the underlying ecological and social selection pressures involved.
KeywordsProblem solving Cognition String pulling Brain size Physical cognition Selection pressure
This work was supported by grants from the Agence Nationale de la Recherche (ANR) (Cognition and Tool-use Economy project, ECOTOOL, ANR-14-CE30-0015-01; F. Osiurak), and was performed within the framework of the LABEX CORTEX (ANR-11-LABX-0042) of the University of Lyon, within the Investissements d’Avenir program (ANR-11-IDEX-0007; F. Osiurak) operated by the ANR. We thank the Parc des Oiseaux for allowing us to undertake this study. We are grateful to Laurie O’Neill for reviewing the English and for helpful comments, Loup Martineau for drawing Fig. 1, and to Sébastien Marcle for helping with the experiments.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Research involving animals
The animals’ care was in accordance with the guidelines of the University of Lyon.
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