Crows and parrots – brainy birds, but in different ways

By Ed Yong | June 8, 2011 2:00 pm

Uek has a problem. She can see a piece of food through a hole in a plastic box, but she cannot reach it. Fortunately, Uek is a New Caledonian crow, a bird that is both intelligent and adept with tools. She grabs a stick with her bill, pushes it forward through the hole and knocks the morsel onto a slope,. It rolls within her reach, and she tucks in.

Kermit has an even bigger problem. He’s faced with the same out-of-reach snack. He has the same stick and the same smarts. But Kermit is a kea, a green parrot with a sharp, curved beak. He can’t wield a stick with the same precision as Uek with her short, straight beak. So Kermit improvises. He picks the stick sideways in his beak and pushes one end through the hole. He holds it there with his foot, grabs the other end in his beak, and finally (and awkwardly) pushes it at the food. Eventually, he too gets a meal.

Uek and Kermit are members of arguably the most intelligent groups of birds – the parrots and the corvids (the family that includes crows, ravens, jays and magpies). For their size, their brains are roughly as big as those of great apes, and their behaviour can be just as sophisticated. They’ve shown many advanced skills including planning for the future, using tools and solving problems.

Now, Alice Auersperg from the University of Vienna has challenged them to the same task. The obvious question is: which one did better? Who is the brainiest of the bird brains? But that would miss the point.

Animal intelligence isn’t a single thing. There is no standard IQ test for them to sit, and no universal checklist of skills to score them against. Instead, animals have evolved mental abilities to cope with different lifestyles and environments. Many early studies into animal intelligence simply looked at whether animals could or couldn’t perform specific tasks. But it’s far more interesting to see why and how they do different things, and how their own particular brand of intelligence has evolved.

That’s why Auersperg, along with Alex Kacelnik from the University of Oxford, decided to work with two of the planet’s brainiest birds – not to pit them against each other, but to understand how they differ.

She presented five New Caledonian crows and six keas with the same set-up – a puzzle box with food, balanced on a central pole. If the birds could knock the food off the pole, it would roll down a sloped platform into their grasp. There were four ways of doing this: they could pull a string tied to the food; they could open a window and stick their head into the box; they could roll a marble down a chute to knock the food off; or, they could push the food off with a stick. Two of these solutions – the marble and the stick – involved tools, and the others didn’t.

The birds could approach the task in any way they liked. And every time they learned one of the four tricks, Auersperg closed it off, forcing them to find a different solution.

She found that at least one bird of each species – Uek and Kermit – discovered all four techniques, which shows that they’re certainly capable of doing so. But the similarities ended there.

Keas are notoriously inquisitive and attracted to new things. In its native New Zealand, it uses it beak to explore (and destroy) everything from nests to picnic baskets to windshield wipers. All of Auersperg’s keas immediately (and violently) explored all four openings in the box, pulling, tearing, scratching and probing at them. “They seemed to approach the apparatus in a playful, toddler-like manner,” she says. Most of them tried to overturn the box, which Auersperg had to nail to the floor. One of them, Luke, even broke the Plexiglas.

As a result of their gung-ho investigations, they picked up the four solutions to the puzzle far quicker than the crows did. After their first session, they had already discovered at least two or three, and when each one was blocked, they moved onto the next one with great speed.

In stark contrast to the keas, New Caledonian crows shirk from novelty. Rather than rushing in beaks first, they explored the box by sight before giving it some tentative pecks. One of them never even went near it. As such, it took them longer to pick up the different solutions.

But the crows had an edge – they’re natural tool users. In the wild, they manufacture their own tools to “fish” for insect grubs buried within decaying logs. In captivity, they’ve chosen the right tool for different jobs, combined different tools together, and improvised from unusual materials like wire hangers. Keas, however, aren’t natural tool users and their beaks are too curved to wield sticks with grace.

It’s not surprising then, that the crows were more adept than the keas at using the sticks to reach their food. All the crows managed it; of the keas, only Kermit did so with his complicated technique. The crows’ fondness for sticks didn’t always work to their favour. They would often try to poke the window with their sticks, while the keas soon learned to pull them open using handles. Even when Uek did lift the window, she still prodded at the food with her stick when she could have just stuck her head through.

These are all captive animals that have taken part in various experiments before (although nothing quite like the puzzle box). Still, Auesperg expects that their behaviour would mirror that of their wild cousins, and says that several studies are now being done with wild birds.

In the meantime, these results clearly show that while both birds are capable of impressive feats of problem-solving, but react differently to the same task. They’re influenced by their anatomy: crows have straight bills but keas have curved ones. They’re influenced by their predispositions: keas like new things, crows shy away from them. They’re influenced by their environment: keas dig haphazardly for food, crows are used to precise prodding.  An animal’s mental skills don’t evolve in a vacuum – they are tailored to that species’ body, lifestyle and environment.

This means that it’s hard to say anything about general skills such as problem-solving, memory or self-awareness based on an animal’s performance at a specific task. It’s important to use a battery of tests, such as the four “solutions” to Auesperg’s puzzle box.  Even then, an animal’s performance may depend more on its attitude to novelty, motivation or body shape than its mental abilities.

Auersperg’s study is a breath of fresh air. It appreciates that “intelligence” looks very different from species to species based on their evolutionary context. Rather than simply ranking her birds against one another, she catalogued the differences between them and looked at why those differences exist. These are more interesting questions than the bland one of which one’s “better”.

PS Uek has a distinguished pedigree. He’s the son of Betty, a famous New Caledonian crow who has distinguished herself in several past experiments, including one that showed how these birds can combine tools.

Reference: Auersperg, von Bayern, Gajdon, Huber & Kacelnik. 2011. Flexibility in Problem Solving and Tool Use of Kea and New Caledonian Crows in a Multi Access Box Paradigm. PLoS ONE http://dx.doi.org/10.1371/journal.pone.0020231

More on corvids and parrots:

Comments (13)

  1. “Animal intelligence isn’t a single thing. There is no standard IQ test for them to sit, and no universal checklist of skills to score them against”
    I would say the same as for human intelligence. Not sure it’s even possible to quantify with a decent degree of accuracy intelligence, least of all scoring it in a linear scale such as the IQ test does

  2. Yes! Bravo. I am uneasy with calling animals “intelligent”. Because by doing so, we seem to imply that other animals are stupid. We are the ones who are being short-sighted by demanding that an octopus should perform stupid human tricks in order to prove its worth. Squid, for example, evolved perfectly for the ecosystem in which they live. They also perform free ecosystem services which are invalueable (do people realize what percentage of Earth’s oxygen comes from plankton)?

    I liked Auersperg’s experiment and I often wonder if prey animals tend to have less dexterity with tools and such than do predators or more “aggressive” species.

  3. Amy

    I’m confused. The first paragraph describes Uek as a female, but the postscript says Uek is Betty’s son.

    Could you clarify, please? Thank you!

  4. Brian Too

    Really interesting. I particularly liked the descriptions of novelty seeking and avoiding preferences. In my experience corvids are very wary (though not in all circumstances) and this validates what I’ve seen first-hand.

    Isn’t mental dexterity and adaptability a sort of meta-skill?

  5. It’s cool the way that different strategies can still get you through the puzzle. And the way each bird did his best with what he had.

  6. Theresa

    Great article, but I feel the need to update you on one point:

    ‘Kea’ is a Maori word. In Maori, there is no ‘s’ for plural endings. Thus, the proper way to pluralize ‘kea’ is to leave it as it is, with no ‘s’.

    The same goes for the name of New Zealan’s national bird, the kiwi, which remains spelled the same in both plural and singular forms. It’s thus very easy for New Zealanders to understand the difference between these two sentences:
    “The kiwi were caught mating.”
    “The Kiwis were caught mating.”

  7. Luisa

    @Emmy: A professor at my university was famous for his work with lizards. He defined intelligence as the ability to solve one’s problems: something lizards have done surpassingly well for a long, long time… humans, not so much.

  8. AHHHHHHHHHHHH I WANT THIS JOB!!!!!!!!!!!!!! <3<3<3

    The kea looks way cuter doing everything, if that counts for anything in this experiment.

  9. Trond Engen

    Theresa: ‘Kea’ is a Maori word. In Maori, there is no ‘s’ for plural endings. Thus, the proper way to pluralize ‘kea’ is to leave it as it is, with no ‘s’.

    That depends on how naturalized the word is in English and (quite likely) the variety of English. ‘Kea’ seems to have entered Ed’s British English (and other non-NZ Englishes) as a singular noun and is thus inflected according to British English morphology, just like most other loans through history. I say non-NZ because the situation in NZ English may be different; the ready presence of Maori may have led to separate borrowings of the singular and plural forms, or the sociolinguistic situation may require a different approach to originally Maori words than to other loans.

  10. @Luisa Ha – well, we certainly over-use the reptilian part of our brain relative to how much we pat ourselves on the back for being so smart. I like the professor’s defenition of intelligence. Since each species has unique problems to solve, I wonder if his defenition would apply more to individuals within a species than between species.

  11. We have a parakeet who displays similar behavior to Uek in the sense that as soon as we close off one path of destruction, she takes delight in discovering another. This is why we now keep paper towels inside a cover, have covers for our seat covers on the kitchen chairs, and keep any papers and books that we value away from “her” zone. I do let her take bites out of the bills though. It makes me feel better when I pay them with an imprinted coupon. Probably the only reason I haven’t switched to all e-payment!

  12. John

    Perhaps Uek wasn’t willing to stick his head in the strange box. Maybe he prodded the food after opening the window out of caution, rather than not realizing he could stick his head in there. My guess is Uek thought it was a bad idea to do so and used the stick instead.

  13. shelley

    Raven is very clever also, a well known trickster but one afternoon I witnessed a lonely raven arranging a piece of debris on the ground, mounting it and then masturbating. If the debris got dislodged or slipped he/she would rearrange it and resume the behaviour. The entire time it was clucking quietly. A good use of tools and no food reward!

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