Animal Acumen: Feathered Apes

Next time someone calls you a birdbrain, just say, "thank you." Research indicates that members of the crow family are more intelligent than chimpanzees, at least in certain ways. Perhaps this shouldn't surprise us; there are certainly clever birds in folklore. Here's an example:

"In a spell of dry weather, when the Birds could find very little to drink, a thirsty Crow found a pitcher with a little water in it. But the pitcher was high and had a narrow neck, and no matter how he tried, the Crow could not reach the water. The poor thing felt as if he must die of thirst. Then an idea came to him. Picking up some small pebbles, he dropped them into the pitcher one by one. With each pebble the water rose a little higher until at last it was near enough so he could drink."

This familiar fable was probably intended to tell us more about ourselves than about crows. Just as we don't expect a mouse to repay a kindness to a lion by nibbling through the robes that bind him, we don't hear this story and then assume that a bird can employ this level of intelligence to earn itself a drink.

Image from The ÆSOP for Children, Illustrated by Milo Winter. The Crow and the Pitcher.

However, it appears we may be underestimating that crow. The rook (Corvus frugilegus), a bird in the same family as crows, ravens, and blue jays, has a brain the size of walnut, but can perform some tasks that confound even our chimpanzee cousins. Dr. Nathan Emery, a researcher at Queen Mary University of London, and his colleagues demonstrated that when confronted with a container of water with a worm floating out reach of their beaks, rooks figure out how to drop rocks into the water to raise the worm high enough for them to reach it. Even more impressively, they know how many stones to use and realize that large stones accomplish the task much more quickly than small ones.

That these birds can solve the puzzle the first time they see it--which not even all primates can do--must "change people's perceptions of what birds are capable of," Emery said. "They are no longer bird brains, but feathered apes."

The fact that rooks do have these capabilities is interesting enough, but researchers want to know how they do it. How does their intelligence relate to brain size and structure?

Neuroscientists love to talk about structure equaling function. In other words, if an animal demonstrates an ability, a behavior, there must be something in its brain that allows it to happen. In this case, birds have brains that are much smaller--and differently structured--than those humans or apes. Emery wonders if there is something in this brain structure that can process information more efficiently than the primate brain does, thus allowing the birds a great deal of cognitive processing with a relatively small neural volume.

Image courtesy of Paul Brentnall/ Rook.

Rooks demonstrate "flexible intelligence," Emery said, meaning they can adapt to different environments. The birds Emery used in his studies were raised in captivity, with everything they needed provided. Did this environment allow them to focus their cognitive abilities on other things, such as solving the puzzles scientists put in front of them? Wild birds too have to face new challenges as they increasingly live in urban environments, where "we may be seeing an example of cognitive evolution 'in action,'" Emery said. Over many generations, city living may fundamentally change these bird brains. In the shorter term, birds may pass their cognitive skills on to their offspring through social learning. In this, rooks seem to demonstrate the same neuroplasticity (the brain's ability to change, both structurally and functionally, as a result of the environment) as their cousins the songbirds. The brains of these birds have been shown to generate neurons at certain times of the year, in response to reproductive or environmental pressures that require increased cognitive capacity.

And what does all of this tell us about ourselves, when even birds have cognitive abilities that we once thought were uniquely human, such as the causal reasoning demonstrated by Emery's rooks? Professor Nicky Clayton of the University of Cambridge has shown that the Western Scrub Jay (another member of the crow family) is capable of mental time travel (remembering the past or imagining the future) and theory of mind (the ability to guess what another individual is thinking or feeling)--both of which are generally thought of as sophisticated cognitive abilities. Perhaps these demonstrations of animal intelligence indicate that we are not as exceptional as we would like to believe.

Clayton, who also happens to be Emery's wife, talked with NOVA about her work and why she thinks birds are intelligent.

This post is part of the series Animal Acumen, an exploration of animal cognition. Visit other posts in this series.

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