Functional tool use requires the selection of appropriate raw materials. New Caledonian crows Corvus moneduloides are known for their extraordinary tool-making behaviour, including the crafting of hooked stick tools from branched vegetation. We describe a surprisingly strong between-site difference in the plant materials used by wild crows to manufacture these tools: crows at one study site use branches of the non-native shrub Desmanthus virgatus, whereas only approximately 7 km away, birds apparently ignore this material in favour of the terminal twigs of an as-yet-unidentified tree species. Although it is likely that differences in local plant communities drive this striking pattern, it remains to be determined how and why crows develop such strong site-specific preferences for certain raw materials.

中文翻译：

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新喀里多尼亚乌鸦使用钩形工具制作材料的地点间差异很大。

使用功能性工具需要选择适当的原材料。新喀里多尼亚乌鸦Corvus moneduloides因其非凡的制作工具性能而闻名，包括从分支植被中制作钩状钩工具。我们描述了野生乌鸦用来制造这些工具的植物材料之间的惊人的站点间差异：一个研究站点的乌鸦使用非本地灌木Desmanthus virgatus的分支，而仅在约7 km处，鸟类显然忽略了这种材料。有利于尚未发现的树种的末端细枝。尽管本地植物群落的差异可能会驱动这种引人注目的模式，但是还有待确定的是，乌鸦如何以及为什么对某些原材料表现出如此强烈的针对特定地点的偏好。