From ScienceDaily.
Researchers have found that New Caledonian crows–which are known to make complex food-getting tools in the wild–can also spontaneously use one tool on another to get a snack.
It appears that the birds may have solved the problem that confronted them by using analogical reasoning rather than simple trial and error. Analogical reasoning requires the ability to see a novel situation as being essentially the same as a previous situation, the researchers explained.
In the study, the researchers presented crows with some meat in a hole and a stick that left the meat out of reach. The birds needed to get a long stick out of a “toolbox” in order to get the meat from the hole. However, the long stick was also out of reach. “The creative thing the crows did was to use the short stick to get the long tool out of the box so that they could then use the long stick to get the meat,” said Alex Taylor, also of the University of Auckland.
In a second experiment, the researchers reversed the positions of the two sticks so that the small stick was inside the toolbox and the long stick was handy. The crows then briefly probed the box containing the short stick with the long stick before correcting their error by taking the stick directly to the hole.
Gray said. “Six out of seven birds tried to get the long stick with the short stick at their first attempt at solving the problem. To do this, they had to inhibit their normal response of trying to get the food directly with the short stick and realize that they could use the short stick to get the long stick.”
Behavioural Ecology Research Group provide many details on the research of New Caledonian crows tool making and using behaviour.
New Caledonian crow tool manufacture and use - University of Auckland.
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Tiny “Crow-Cams” Capture Tool Use in Wild Birds. (National Geographic News)
Ultralight video cameras fastened to the tail feathers of crows have shown the birds to be versatile tool-users in the wild.
The 13-gram (0.5-ounce) cameras—slightly heavier than two U.S. quarters—provide the closest thing yet to a bird’s-eye view of behavior in a natural setting.
“The lens is pushed forward through the central tail feathers and peeks through the bird’s legs,” Rutz said. “You have a shot showing part of the crow’s belly and whatever appears in front of the bird.”
Video footage showed that the crows also forage extensively on the ground, using a previously unreported type of tool—stalks of grass—to turn over loose material in search of insects.
Another discovery was that the crows did not always use whatever stick or stem was close by to serve as a foraging tool.
In one instance, Rutz said, a favored tool was used over a prolonged period of time and carried in flight from one location to another.
Each crow-mounted camera contained a radio beacon that allowed researchers to track the bird’s location during and after filming and to eventually retrieve the camera.
Researcher and filmmaker Greg Marshall is a pioneer in the use of animal-mounted video for research and the inventor of National Geographic’s Crittercam.
Because battery weight is a major constraint in ultralight video systems, Marshall noted, cameras on birds cannot currently be deployed for periods of days or weeks.
Crows never seem to forget a face. (IHT)
Crows make monkeys out of chimps in mental test. (NewScientist)