ABSTRACT

The New Caledonian crow (Corvus moneduloides) is known for displaying a unique set of tool-related behaviours, with the bird’s bill acting as an individually consistently lateralized effector. However, we still fail to understand how such laterality develops, is modulated or even if its expression is consistent across other behavioural categories. Creating the first ethogram for this species allowed us to examine laterality and vocalisations in a population of wild, free-flying New Caledonian crows using detailed analyses of close-up video footage. We revealed the existence of an overall strong left-sided bias during object manipulation only and which was driven by the adult crows of our focal population, the stabilization of individual preferences occurring during the birds’ juvenile years. Individually, at least one crow showed consistent side biases to the right and left within different behavioural categories. Our findings highlight previously unknown variability in behavioural laterality in this species, thus advocating for further investigation. Specifically, we argue that a better understanding of the New Caledonian crow's biology and ecology is required if one wishes to pursue the promising comparative road that laterality could be connected to the evolution of tool-making.

摘要

新喀里多尼亚乌鸦 ( Corvus moneduloides) 以展示一组独特的与工具相关的行为而闻名，鸟类的喙作为一个单独一致的侧向效应器。然而，我们仍然无法理解这种偏侧性是如何发展、调节的，甚至它的表达在其他行为类别中是否一致。为该物种创建第一个动物行为图使我们能够使用特写视频片段的详细分析来检查野生、自由飞行的新喀里多尼亚乌鸦种群的偏侧性和发声。我们揭示了仅在对象操作期间存在整体强烈的左侧偏差，这是由我们的焦点人口中的成年乌鸦驱动的，个体偏好的稳定发生在鸟类的幼年期。个别地，至少一只乌鸦在不同的行为类别中表现出一致的左右偏向。我们的研究结果突出了该物种先前未知的行为侧向变异性，因此提倡进一步调查。具体来说，我们认为，如果人们希望走一条有前途的比较道路，即侧向性与工具制造的进化有关，那么就需要更好地了解新喀里多尼亚乌鸦的生物学和生态学。