title: The ecological significance of tool use in New Caledonian crows.
abstract: Tool use is so rare in the animal kingdom that its evolutionary origins cannot be traced with comparative analyses. Valuable insights can be gained from investigating the ecological context and adaptive significance of tool use under contemporary conditions, but obtaining robust observational data is challenging. We assayed individual-level tool-use dependence in wild New Caledonian crows by analyzing stable isotope profiles of the birds' feathers, blood, and putative food sources. Bayesian diet-mixing models revealed that a substantial amount of the crows' protein and lipid intake comes from prey obtained with stick tools--wood-boring beetle larvae. Our calculations provide estimates of larva-intake rates and show that just a few larvae can satisfy a crow's daily energy requirements, highlighting the substantial rewards available to competent tool users.
authors.affiliation: Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK. christian.rutz@zoo.ox.ac.uk
authors.forename: Christian
authors.initials: C
authors.lastname: Rutz
authors.forename: Lucas A
authors.initials: LA
authors.lastname: Bluff
authors.forename: Nicola
authors.initials: N
authors.lastname: Reed
authors.forename: Jolyon
authors.initials: J
authors.lastname: Troscianko
authors.forename: Jason
authors.initials: J
authors.lastname: Newton
authors.forename: Richard
authors.initials: R
authors.lastname: Inger
authors.forename: Alex
authors.initials: A
authors.lastname: Kacelnik
authors.forename: Stuart
authors.initials: S
authors.lastname: Bearhop
mesh_terms: D031284:Aleurites; D000818:Animals; D001499:Bayes Theorem; D002247:Carbon Isotopes / Q000032:analysis / Q000097:blood; D001517:Coleoptera; D046368:Crows / Q000502:physiology*; D004032:Diet; D005241:Feathers / Q000737:chemistry; D005247:Feeding Behavior; D005260:Female; D007814:Larva; D008297:Male; D009510:New Caledonia; D009587:Nitrogen Isotopes / Q000032:analysis / Q000097:blood; D009754:Nuts; D053001:Tool Use Behavior
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes