Source: Nature: "Ravens"
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Within their own communities, young ravens can be quite cooperative. The ability to share and work together is an example of ravens' very practical intelligence. It allows them to survive as a collective where they might fail as individuals. In this video segment from Nature, ravens use body language and vocalizations to exchange information on the location of a food source.
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The traditional view of birds was that they simply acted by a set of inherited instincts, but new scientific research is revealing a larger role for complex cognitive processes in their behavior, including communication, counting, memory, and basic problem solving. Ravens, known as the brainiest of all birds, demonstrate several of these commonly accepted indicators of animal intelligence.
These roosts sometimes number thousands of young birds. It’s like a great gathering of teen-agers.
John Marzluff: The raven roost is a really exciting place to be, there's a lot of interesting behavior and incredible flying skills that are displayed at the roost, and there are a couple of things that interest us in particular. The first question of why they even roost together is, again, a difficult one to answer. There are probably many reasons why ravens and other animals roost communally, but one of the most interesting ideas was that they actually roosted together to share information about where their food was.
A young, inexperienced bird may not have eaten all day.
John Marzluff: And an animal that was unsuccessful could come back to the roost and pick the brain of animals that were successful that day.
It's not clear how ravens share information though this may happen on many levels. Certainly their vocalizations are as complex as any animal’s. A simple way could be for a hungry raven to follow one that looks well fed. If it found food yesterday it's likely to find it again today.
When a raven returns to a carcass, there may be several birds already following it.
Yet instead of keeping all the food for themselves, one or more ravens sometimes make a characteristic yell that seems to be calling even more of them to the kill.
This behavior has puzzled scientists - why don't the first ravens to arrive keep silent – and keep all the food for themselves? What do these ravens gain by calling others to join them? It appears to violate almost everything we know about animal behavior. Ravens must have some reason for doing this.
John Marzluff: Why when you find a dead moose in the woods would you ever want to recruit a hundred hungry ravens to eat it? You know it doesn't make any sense. Darwin would have been flipping in his grave thinking about such an altruistic act.
The answer is about competition, but not from the outside. This carcass is in the territory of a pair of adult breeding ravens – and established pairs can be very aggressive. They would savagely attack any youngster who invaded their turf. By forming a cooperative gang, the young ravens can outnumber the resident adults – and help themselves to the carcass.
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