, Volume 38, Issue 3, pp 206-219

Social learning in new Caledonian crows

Abstract

New Caledonian (NC) crows are the most sophisticated tool manufacturers other than humans. The diversification and geographical distribution of their three Pandanus tool designs that differ in complexity, as well as the lack of ecological correlates, suggest that cumulative technological change has taken place. To investigate the possibility that high-fidelity social transmission mediated this putative ratchet-like process, we studied the ontogeny of Pandanus tool manufacture and social organization in free-living NC crows. We found that juvenile crows took more than 1 year to reach adult proficiency in their Pandanus tool skills. Although trial-and-error learning is clearly important, juveniles have ample opportunity to learn about Pandanus tool manufacture by both observing their parents and interacting with artifactual material. The crows’ social system seems likely to promote the faithful social transmission of local tool designs by both favoring the vertical transmission of tool information and minimizing horizontal transmission. We suggest that NC crows develop their Pandanus tool skills in a highly scaffolded learning environment that facilitates the cumulative technological evolution of tool designs.

We thank William Wadrobert for kindly allowing us to work on his family’s land in Wabao District, Maré, and the Province des Iles Loyauté for permission to work on Maré. Mick Sibley prepared DVD versions of the video footage. Noel Andrews, Lindsey Davidson, Roland Rehm, Robert Ross, Mick Sibley, and Alex Taylor assisted with data collection. We thank Katie Palmer for help with the coding of video footage, Puja Singh for help with the coding and processing of the sociality data, Vivian Ward for drawing Figure 3, and Roland Rehm for the production of Figure 5. Jeff Galef provided many helpful comments that improved the manuscript. This research was funded by a grant from the New Zealand Marsden Fund (awarded to R.D.G. and G.R.H.). The research reported in this article was approved by the University of Auckland Animal Ethics Committee (approvals R231 and R375) and complies with the laws of New Caledonia.