The Crow and the PitcherComing upon a pitcher of water left in a garden, the crow tries to drink from it, but there is only a little water left at the bottom, and his beak can’t reach it. Having thought for a while, the crow came up with a the solution, dropping in pebbles until the water level rose enough for him to drink.
An Aesop Fable
Modern researchers have repeated this classic story in an experiment, with a slight twist. Instead of dehydrating the bird they presented it with a tasty worm floating in the water.
The rooks that Emery and Bird(!) used in their experiment replicated the fable almost to a fault. They thought about it for a while, sizing up the problem and using the pebbles to make the water rise.
In fact they went one better, rather than picking random pebbles they chose them for size and went for the most efficient solution. "It's as if they were estimating the number of stones they needed right from the start,"
Emery and Bird also reflect on the similarity in intelligence between crows and primates, a group for which it is generally excepted that they are highly intelligentOur data also provide further evidence for the idea of convergent cognitive evolution in these two distantly related groups. This is particularly interesting because the brains of birds and mammals are structurally very different.
Article in Science
Full paper in Current Biology
(more videos and graphs)
Aesops's fable: http://www.mythfolklore.net/aesopica/oxford/453.htm