image: This is a schematic illustration of the study rationale. New Caledonian crows consume a range of foods, but require tools to extract wood-boring beetle larvae from their burrows. These larvae, with their unusual diet, have a distinct isotopic signature that can be traced in the crows' feathers and blood. By comparing the stable isotope profiles of the crows' tissues with those of their putative food sources, the proportion of larvae in crow diet can be estimated, providing a proxy for individual-level tool-use dependence. This image relates to an article that appeared in the Sept. 17, 2010, issue of Science, published by AAAS. The study, by Dr. Christian Rutz of the University of Oxford, and colleagues was titled, "The Ecological Significance of Tool Use in New Caledonian Crows." view more
Credit: Schematic: © Christian Rutz and Jolyon Troscianko