New Caledonian crows (Corvus moneduloides) have remarkable tool-using abilities that are at least as sophisticated as those of chimpanzees, if not more so. To date, however, such behaviours have only been observed in contrived experimental conditions.
Using newly-developed mitinuarized animal-borne video cameras, researchers have now filmed wild crows using tools. The footage they have obtained is the first to show the use of tools by crows in their natural habitat.
Used in combination with conventional radio telemetry, the tail-mounted cameras provided the researchers with detailed information about the behaviour of the crows in their natural environment, including their overall activity patterns, modes of foraging, choice of diet, and encounters with prey. The findings are published online in the journal Science.
Christian Rutz and his colleagues at the University of Oxford mounted the miniature cameras on the tails of 18 wild, free-ranging crows. They obtained about 7.5 hours of footage of the the natural foraging behaviour of the birds, which revealed hitherto unknown aspects of their use of tools.
For example, one of the crows observed in the study used at least 3 different tools while foraging for food in loose substrate on the ground. The tool was transported from one site to another, and discarded briefly while the crow used its beak. Use of the tool was then resumed.
This film shows the crows making tools from what appears to a dry, grass-like stem. Prior to this study, crows had never been seen using this material for tool-making.