Social Necessity Makes Birds Smart.
Scientists believe it is not physical need that drives creatures to become smarter, but social necessity. The complexities of living together require a higher level of intelligence. Corvids and parrots, along with dolphins, chimps, and humans are all highly social--and smart--animals.
Some ravens certainly apply their intelligence for the good of the flock. In North America, they contact other ravens to tell them the location of a carcass. Ravens are specialized feeders on the carcasses of large mammals such as moose during the harsh winter months of North America. The birds roost together at night on a tree, arriving noisily from all directions shortly before sunset. The next morning, all the birds leave the roost as highly synchronized groups at dawn, giving a few noisy caws, followed by honking. They may all be flying off in the direction taken by a bird, which had discovered a carcass the previous day. This bird leads the others to his food store, apparently sharing his finding with the rest of the flock.
Ravens share information about their findings of food carcasses because dead animals are patchily distributed and hard to find. Many eyes have a better chance of finding a carcass, and once one has been located, the information is pooled. Although the carcass now has to be shared between more individuals, the heavy snowfall and risk of mammal scavengers taking the food mean that a single bird or a small group could not eat it all alone anyway.
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