We thank the Province Sud and SEM Mwe Ara, New Caledonia, for research permits and access to our study site and facilities, T. Mennesson and C. Lambert for invaluable support, S. Wischnewski, J. van der Wal, Z. Burns and several field assistants for help with bird trapping and husbandry and/or running trials, and A. Péter for technical advice on Solomon Coder software. We are grateful to J. Call, L. Dean, K. Laland, A. Magurran and L. Rendell for providing insightful and constructive comments on earlier drafts. Experiments were approved by Oxford University’s local ethical review committee before the group’s transfer to the University of St Andrews. The study was funded through a Biotechnology and Biological Sciences Research Council David Phillips Fellowship (grant BB/G023913/2 to C.R.) and PhD studentships from the Biotechnology and Biological Sciences Research Council (B.C.K.) and the Japan Student Services Organization (S.S.).