Wrong leaves on your favorite bushes are not deceived new Caledonian crows
They are not embarrassed even glued leaves from other plants.
New Caledonian crows, famous for their intelligence, they recognize they need to manufacture the tools plant at leaves and twigs, while they are able to choose the right material for the hook even if replaced by a branch of leaves. The study about it was published in the journal Biology Letters.
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New Caledonian crows (Corvus moneduloides) can not only use but also make tools: when foraging in nature, these birds make the hooks and spines of the branches, which pulls out from under the bark the larvae. Made guns, they sometimes take with them, using them in the future. In addition, the ravens discovered the ability on memory to recreate the tools that they have seen before — so they can transfer their skills to other individuals.
Barbara Klump (Barbara Klump) from St. Andrews University and her colleagues have conducted a series of experiments with 10 crows, to see how ones choose the right materials for their instruments from a variety of plants of the archipelago of New Caledonia. The authors note that sometimes the ravens choose different plants, but sometimes only a particular kind — so, in the population being examined by scientists, the birds preferred the branches of the Bush Desmanthus virgatus.
In the experiment, the researchers used three types of plants: the same Desmanthus virgatus, leucine svetlovolosogo (Leucaena leucocephala) with similar leaves and shrubs of the genus tea tree (Melaleuca) which bird is sometimes also used for the manufacture of tools.
Each bird participated in five ten-minute experiments in which they showed the log where she hid a piece of meat, and two branches of plants.
The scientists watched what plant and how quickly will choose a bird, as well as the fact that it draws attention primarily on the leaves or on the branch.
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The authors write that the ravens clearly wanted Desmanthus virgatus even when a branch of this plant was used like the leaves leucine — and when the branch was not visible (in one experiment the birds through the window showed only the leaves), they reluctantly turned to her, to make the tool.
Interestingly, in the reverse experiment, when the leaves of desmanthus stuck on a branch leucine, all four of the crow of the ten who chose leucine chose in the end, it is these branches with glued sheets of the desired plants, not ordinary branches. This, according to research group, means that the first birds are guided to the branch, and the second — on the leaves, which are easier to quickly identify.
Scientists believe that further experiments are required to understand how new Caledonian crows assess the quality of branches of plants and their suitability for the manufacture of effective tools.
Recently, scientists have discovered that crows can roughly estimate the mass of a subject without contacting them directly, and watching how it moves in the air flow. And before that, another group of researchers were convinced that birds are able to make composite tools from the details of how people and apes.