Crafty Grackles

Why can some birds use tools?
21 May 2015

Interview with 

Dr Corina Logan, Department of Zoology, Cambridge University


This week we're asking what's the most amazing animal? Talking to Ginny Smith, Corina Logan, from the Department of Zoology at Cambridge University, works on Grackle (bird)intelligence in birds, including the grackle. First she wanted to test the intelligence of one of the audience...

Will - I'm Will.

Corina - So, I'm going to ask you Will, if you're going to be able to help me solve this puzzle.

Ginny - Okay, so you're just removing a drape that's been covering up a rather strange collection of objects you've got here on the table. So, we've got in the middle a tall glass tube which is maybe 8 centimetres in diameter and it's about half-full with water. It's about 25 centimetres tall and floating on the top of the water is a little red ball. And then around it, we've got a selection of objects. What kind of objects can you see?

Will - There's some foam, stones, corks, sticks, and leaves.

Ginny - All sorts of weird things. So, what have we got to do here?

Corina - If you can get the ball out of the tube then I will give you a chocolate bar or a piece of fruit leather. But you can't tip over the tube.

Ginny - So, all you can use is those two fingers, your front finger and your thumb has a little sort of pincer action, and you have to say if you can get that ball out, what are going to do?

Will - I think I'm going to put stones in the bottom so the water rises up.

Ginny - Do you want to see if it works? Every time you're putting a stone in there, it's displacing some water and the water level is rising. So, what are you aiming for?

Will - That the water level rises enough so you can take the ball out.

Ginny - Well, done. You managed it. A round of applause. How do you actually go about doing this with a bird?  I mean, you can't tell it to get a ball and swap it for chocolate, can you?

Corina - No, exactly. So, I actually have to train the birds to drop the stones down the tubes and I do this on a different apparatus. So, there isn't water involved. It's just a tube that's on top of a platform. So, you drop the stone down the tube and it collapses the platform and the food was sitting on top of the platform. So then it falls out when the stone goes through the apparatus.

Ginny - So, how long does it take them to learn it?

Corina - It depends. New Caledonian crows can learn it pretty quickly and in maybe around a hundred trials. Great tailed grackles, which is the species I'm promoting today, the fastest one was 165 trials and the slowest was like 392 trials... It took her a while.

Ginny - So, that's a little bit longer than it took our volunteer here who just took one look at it and did the right thing.

Corina - Yeah. So with humans, you can just say, get the reward and they don't need training in how to drop things down tubes because we have a lot of these kinds of experiences, but the birds don't.

Ginny - Why are you doing this with birds? I mean, it sounds like a lot of fun but I'm guessing there's a scientific reason.

Corina - Why I'm doing this particularly with the great-tailed grackle and for those who don't know, is because they're not a bird that lives over on this side of the Atlantic ocean. They're a bird and they're about the size of a jack saw but they have a really long tail, kind of like a magpie. With this particular bird, they actually have an average size brain for their body size while the crows and parrots have these really big brains and so, one of the ideas about brain size is that if you have a larger brain, you should be smarter. But these grackles, I first found them in Costa Rica. I was studying other animals there and I saw these grackles and they come right up to me and they look me in the eye. I think they wanted my food but I also thought, gosh! They look really smart. What I'm finding which is pretty amazing is that even though their brain is, it weighs as much as a 1p coin, they can solve these problems like children that are 5 years of age and older whereas children that are 4 years old, they don't solve these tasks. And they solve them like the large-brained new Caledonian crows and rooks, and Eurasian jays.

Ginny - Yes, so we've known for a while that these other birds that you mentioned, rooks and jays and crows are really, really intelligent. But we've always thought that they have very big brains compared to their body size and that that was why. But this is really throwing all that into the air. These animals have 1p coin. That is tiny. How come they can do this?

Corina - So, the neurons are how the brain is cognitively processing things. So, if you have more neurons, you should be able to do more things cognitively. And so, they have been finding that the number of neurons in your brain does not scale with how big your brain is. So, you can have a very large brain but not very many neurons. I think it's going to come down to looking at how many neurons different species have so that we can make better predictions about how smart an animal should be.

Ginny - Do we know anything about how many neurons your grackles have yet?

Corina - We do not. I'm waiting for some papers to come out this year. I've been waiting and waiting, and I'm really excited to see the results, but we don't know yet.

Ginny - So, it may be that packed into that 1p coin, they've got loads and loads - these cells which are actually doing the work, talking to each other and that's what allows them to be so intelligent.

Corina - Right, exactly.

Ginny - Thanks so much. That was Corina Logan everyone. Before we get to the judges, it looks like we have a question from the audience. What is it you want to ask?

Young Boy - Didn't they do some sort of study about birds using like a wire or a piece of metal to hook their food out of a tube like that?

Corina - Yes, good memory. So, this was work that was at Oxford with the New Caledonian crows. They not only used tools, but they make a lot of different kinds of tools. One of the kinds of tools they make is this hook tool out of sticks. Now, there's another species that's here, the rooks, and they are also able to do this. So in the wild, rooks don't use tools. They don't make the tools, but you bring them into an aviary and you give them a straight piece of wire, they'll make a hook and they'll pull the basket out.

Ginny - Amazing! Over to the judges now. Has anyone got a comment or question for Corina?

Max - You mentioned a few other tasks that crows could do and if you're saying that these birds are really smart despite having tiny brains, have you found any other tricks that they can do?

Corina - So, the grackles are different. They're not tool users and I did check for some tool use in the lab and I did not see that. They tend to flip objects over and look under rocks and things for food as well as digging in our garbage and eating at our outdoor cafés. They love chips and so, as soon as you turn your head, they're on the table, stealing your chips, so they can fly away and eat them. So grackles have slightly different strategies than the crows have.

Ginny - So, watch your chips if you're near a grackle. Okay, let's go over to our judges for your scores now. Let's start with George.

George - 7

Georgia - I'm going to go with 6.

Max - I kind of think you made crows sound more cool than grackles so I'm going to 6.

Ginny - Okay, a round of applause for Corina Logan. Now, let's go over to Heather to see what that's done to our leader's board. Heather, how is it looking now?

Heather - So, our grackles seem to be flying south with 19. The sticklebacks are swimming downstream with 21.5. Caterpillars are crawling just behind our leaders, moles which are clawing onto victory with 26.


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