title: Strong between-site variation in New Caledonian crows' use of hook-tool-making materials.
abstract: Functional tool use requires the selection of appropriate raw materials. New Caledonian crowsCorvus moneduloidesare 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 shrubDesmanthus 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.
authors.affiliation: Centre for Biological Diversity School of Biology University of St Andrews St Andrews KY16 9TH UK.
authors.forename: James J H
authors.initials: JJ
authors.lastname: St Clair
authors.affiliation: Centre for Biological Diversity School of Biology University of St Andrews St Andrews KY16 9TH UK.
authors.forename: Barbara C
authors.initials: BC
authors.lastname: Klump
authors.affiliation: Centre for Biological Diversity School of Biology University of St Andrews St Andrews KY16 9TH UK.
authors.forename: Jessica E M
authors.initials: JE
authors.lastname: van der Wal
authors.affiliation: Centre for Biological Diversity School of Biology University of St Andrews St Andrews KY16 9TH UK.
authors.forename: Shoko
authors.initials: S
authors.lastname: Sugasawa
authors.affiliation: Centre for Biological Diversity School of Biology University of St Andrews St Andrews KY16 9TH UK.
authors.forename: Christian
authors.initials: C
authors.lastname: Rutz
keywords: construction behaviour; corvid; cumulative culture; extractive foraging; innovation; material culture; raw materials selectivity; tool manufacture; tool selectivity; tool use