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Welcome back to SciShow Talk Show where Hank talks to interesting people about interesting things! In this episode Hank discusses corvids with John Marzluff of the University of Washington.

Thank you to the Montana Natural History Center for collaborating with us on this video!

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*intro music*
Hank: Hey, welcome to the SciShow Talk Show, the day on SciShow where we talk to interesting folks about interesting stuff. Today we've got professor of wildlife science John Marzluff from the University of Waaa--Washington.
Hank: There's too many universities in your town. In your state. And I almost said the wrong one, but I said the right one. So that's what matters.
Dr. Marzluff: You did, thank you.
Hank: So how are you doing?
Dr. Marzluff: Great, how are you? 
Hank: Good, good. So you study some kind of wildlife.
Dr. Marzluff: I do. A variety.

 What is a corvid?

Hank: I think you are best known for your work with corvids. What is a corvid?
Dr. Marzluff: It's one of a type of bird that's in a particular family that includes the crows, ravens, magpies, jays, nutcrackers. Quite a diversity.
Hank: And I feel like we hear a lot about these kinds of birds in relationship to their smarts. So, why do we particularly hear about corvids when we hear about things being you know, when we're doing research and being like "Maybe humans aren't so unique in the way that we think."
Dr. Marzluff: Well they're clever, they're inventive. They use tools. They manufacture tools, some species. They have big brains for their body size and they are quick studies. They learn new things--whether it's a vocalization or a behavior or a type of food to eat they learn it *snaps* really quickly, so.
Hank: Is that most of the research that you do, is on the behavior and learning styles of birds?
Dr. Marzluff: Mine's been on a variety of things, really, with the corvids--everything from their social behavior to their role as a threat to other species, because they are also predators. And so, they have increased in response to human activity in many places, some species. And that translates into a challenge for rarer species that live there.
Hank: Interesting.
Dr. Marzluff: Looked at a lot of things, but kind of focusing on brain activity and how the brain allows them to do some of these things now as well.
Hank: It's always a little tricky when we're talking about the intelligence of another species because what do we really know about how even we think, but then moving from out of our species into other species...Do you think we have a tendency to try and apply our understanding of what thought is to other species too liberally?
Dr. Marzluff: Well I think it's the only model we have. You know, you know how you think about things, and visualize and plan, and arrange your actions, and we assume that other vertebrates do it that way. I think it's not too big of a leap frankly because we share a common ancestor, we have the same nervous system, basically, the same cells, the same chemicals that modulate their activity...
Hank: Mm-hmm.
Dr. Marzluff: Even though we're very different animals, there's still a lot of the same machinery there. So why wouldn't some of the experiences and ways of doing things be similar?

 Dr. Marzluff's research in general

Hank: So how does your research function? Is it mostly inside of a laboratory or is there a lot of field work?
Dr. Marzluff: Well, I really like the combination. I've always tried to do field observations and let those observations motivate what kind of things you then might do in the lab. And the lab for me might be literally in the basement of the hospital doing brain imagery or it might just be a big aviary where you try to keep things as natural as possible but just vary one or two factors at a time to really understand things. But it's all motivated by what you see animals do in nature.
Hank: So you're actually taking a bird and putting it through some kind of of imaging scan while it's conscious to see how that functions? Or is it just...
Dr. Marzluff: So it's an interesting...that would be one way to do it but you would have to have the animal stay perfectly still.
Hank: Yes. Just tell it! You said they're smart.
*both laugh*
Dr. Marzluff: Lay down and relax, yeah. Uh, no. They've done that with some dogs, now. They've trained some dogs. But it's got to fail more times than it works, you know. The real key is that the animal has to be perfectly still or you do not get a quality image.
Hank: So the way to get a perfectly still animal is to have a dead one, usually.
Dr. Marzluff: Or anesthetize it.
Hank: Okay.
Dr. Marzluff: And that's what we do.
Hank: So you're actually using living....
Dr. Marzluff: We anesthetize the birds. But, the cool thing is, the technique we use, which is called PET imagery, it's not the MRI that you might thing of when you think of brain scans. It's like that, but it tracks where there's a lot of energy demands being brought to the cells as opposed to blood flow.
Hank: Oh okay.
Dr. Marzluff: And the nice thing is that you can give the birds a tracer that simulates glucose that's supplying the energy, but it's got a radioactive label, and you let the bird do its behavior while it's assimilating that glucose mimic, and the label, the radioactive label, stays in the parts of the brain that were active at that time.
Hank: Right, right.
Dr. Marzluff: Then you anesthetize the bird, scan it, and basically look back in time at what's going on in its brain.
Hank: And so you can see that there are analogous structures to what we might have doing an activity as a human.
Dr. Marzluff: Yes.
Hank: I imagine that a bird brain and a human brain...have similar parts. But have a lot of functional differences.
Dr. Marzluff: There's some similar parts and there's some very different parts. One that is homologous between humans and birds the hippocampus, the center of memories, especially spatial or social memories.
Hank: That's an older part of the brain, right?
Dr. Marzluff: It's an older part of the brain. It's a part of the limbic system that you hear about. And it's very important for us navigating and remembering and doing a lot of the pretty sophisticated sort of behaviors that we do. Well birds have those as well. And we've shown that that part of the crow's brain, for example, is used to learn about dangerous situations. Things that are associated with the sight of a dead crow, when a crow sees another dead crow, the hippocampus is activated. So they're presumably learning the set, or the people and other things that are around it at that time.
Hank: Interesting research, you're just like showing crows dead crows.
Dr. Marzluff: We, yeah. It is kind of weird. *chuckles* But, what else do you?
Hank: It's interesting that that's a significant psychological event for a crow, to see another dead crow.
Dr. Marzluff: Yes. It is. And it's not black and white, like it isn't for us. If we see a dead person that we don't know, or in a different situation, a young or an old person, you might react differently. An old person, "okay, well, it's their time". Young person, "what a shame". You might have a very different emotional and brain reaction to that. So we're finding with some ongoing experiments now that birds do react differently. Crows react differently to the sight of a young or an old dead crow. They react differently probably to one they know versus don't know we haven't been able to do that experiment yet. You can imagine the ethics of it are beyond what I would be willing to do.
Hank: Right.
Dr. Marzluff: But they probably respond in a very nuanced way to a dead crow as well.

 Crows recognizing human faces

Hank: Fascinating. So, I've heard also that crows are able to very easily recognize human faces.
Dr. Marzluff: Yes.
Hank: How do you know that?
Dr. Marzluff: We always suspected it, when we would go out and study crows, one thing you have to do is catch them or climb to their nest and look at their young or their eggs. And so you're threatening to them when you do that. And so we always suspected they were very responsive to us after an event like that: they either hid from us or they scolded us, or they tried to sneak around in ways that we couldn't follow them as easily.

 The Experiment

(7:45) Dr. Marzluff: And so we decided to do an experiment. We decided to wear a mask to change our identity--
Hank: And that wasn't more scary? Because if someone is climbing up in my house wearing a mask....That's definitely two steps more than the drunk guy who doesn't know which house he's at.
Dr. Marzluff: *nods* Well, it was more scary to the owners of the homes where we did this, absolutely.
Hank: *laughs*
Dr. Marzluff: To the birds I don't think it mattered, it was still a predator climbing up to their nest. But it allowed us to hand off that identity to different people and have them encounter the birds and see the response after we did something. In our case we captured them for this, instead of climbing to their nest. They responded dramatically after a person had captured them when the saw that person again. And it didn't matter if it was you wearing it or any of us wearing it. That face, that's what they responded to.

 Fascinating scientific moments

Hank: What do you think, over those last, oh, 35 years, have been the most fascinating moments for you as a scientist?
Dr. Marzluff: Well, those rare moments of discovery. They're hard to imagine, what they're going to be. When you look back on them they're very important to us, but at the time you really don't know. So I would go back to the first time when we did this facial recognition testing. To be honest with you, we kind of started it as a joke. We thought this happened, nobody had actually directly tested it, and we thought "This is a simple experiment. We'll just do this." And we compared of the crows to a caveman mask versus Dick Cheney as the other mask. And you know, I thought this is going to be an experiment we do in a few week's time and we're done. And we can just have a neat slide to make people laugh about it.
Dr. Marzluff:  Well, now, 10 years later, the birds are still recognizing that dangerous face, and amazing me, frankly, every time I go out and they respond to that caveman that we used to capture them. Because I thought...I wasn't even sure if they would initially at all and they did, very strongly. And then to have continued and to have passed it on to others that didn't experience it, has been...
Hank: Oh wow.
Dr. Marzluff: Has been really interesting.
Hank: So they pass...they are able to have that information passed...?
Dr. Marzluff: They are able to socially learn information, and in this case we know that the great majority of birds that attack us now when we wear that mask weren't even born when we actually captured the birds.
Hank: So you have not captured the birds with that mask since?
Dr. Marzluff: 10 years.
Hank: Wow.
Dr. Marzluff: Yeah.
Hank: And they're big fans of Dick Cheney?
Dr. Marzluff: Um, they're starting to...
Hank: Dick was the control?
Dr. Marzluff: Dick was the control and they were big fans of his to begin with, they didn't care at all, but now they're starting to think he might have had something to do with it as well.
Hank: *laughs*
Dr. Marzluff: And they're definitely scolding him more. I think they're starting to generalize. It's a mask, now, as opposed to which mask.
Dr. Marzluff: We showed initially they could distinguish very fine differences in masks, but now I think it's kind of "uhhhh...could be another bad guy."

 Animal Guest, Intro

Hank: Well we have a corvid to interact with. This is it named Rook? Rook is a little bit shy, as you might expect, but always amazing to be up close a raven, which are just fascinating and surprisingly gigantic birds.
Dr. Marzluff: Yes, Yes.
Hank: Yes, so....let's have Rook show up.
Hank: Great.

 Animal Guest: Rook the Raven

Jessi: Good job, buddy!
Hank: It's nice to have a guest who's experienced at this...being nearby the animal. How much time have you spent close to ravens?
Dr. Marzluff: Quite a lot. I did three years of work in the woods of Maine with ravens and we were catching ravens and monitoring them in the wild as well as in big cages. We had a pair that bred and raised young, we had them living alongside our house...we were living like ravens, my wife and I, for three years up there it was awesome.
Jessi: Awesome, oh wow. So yeah, what do you think of his behavior right now?
Dr. Marzluff: He's very curious. He's looking, a lot of birds would---
Rook: *flapping, ruffling voices as he falls*
Dr. Marzluff: Yeah
Jessi: There he goes.
Dr. Marzluff: They would just be freaked out.
Jessi: I gotcha.
Dr. Marzluff: Or they would be very unobservant,
Jessi: They close down.
Dr. Marzluff: A raptor would close down, they might be looking at a few places looking for a place to get out. He's probably, he's checking us out but he's also just looking like "How do I get out of here?"
Jessi: He is, he's like "wait a second". We have to work really hard to keep him from getting bored and depressed and hurting himself or any of those things.
Dr. Marzluff: Do you have toys for mess with?
Jessi: So many toys. So he's like, he gets like children's toys, like one to five-year-old toys, puzzles, and other things. He loves those. The rope pulling-up things, we hang things from ropes from his perches
Dr. Marzluff: He does that?
Jessi: He does it. He does it. I don't know where he learned it but we did it and he didn't touch it when we were watching and then I went back and it was gone. The food was massacred.
Jessi: So the interesting thing that just recently happened. We've had him for almost two years now, and we clean him regularly but we...found one of his stashes. So we thought he was eating all of his food. He gets a mixture of a whole bunch of different stuff, and one of the things is dog food, because they love dog food, and it's good for them too. And so we found this stash and it was under his water dish, so far under that we couldn't see it, and the only way he could have gotten it under there is if he would have pushed it with a tool. A stick. So he is hiding his food with tools.
Dr. Marzluff: Nice.
Jessi: And he's doing it on the covert, like we had no idea it was going on.
Dr. Marzluff: Have you seen him now do that?
Jessi: No, no.
Dr. Marzluff: So he doesn't let anybody see it.
Dr. Marzluff: Sneaky...yeah.
Jessi: (to Rook): Where you goin'? I think we should go back now.
Hank: Yeah
Jessi (to Rook): We can call it a day, you did amazing, Rook.
Hank: You did so good.
Jessi: And..yeah, we're gonna go again. Alright, come on buddy.
Hank: Just let us know if you need a band-aid.
Jessi: We're good. Good job, buddy.

 Closing Discussion

Hank: I want to know more about...I just want to see what Rook does in his spare time.
Jessi: I know! I want to put one of those 24-hour cams up
Hank: Like a webcam
Jessi: Yup, and see what is he doing?
Dr. Marzluff: We just got one of those for our aviary, so we're going to have four cameras in there now, all the time.
Jessi: Nice!
Dr. Marzluff: So, this is the kind of thing yeah, you come into the cage the next day and it's like "hmmmm...something's gone on here and I have no idea what"
*all laugh*
Jessi: Yup, yup. We've experienced with..So we started...all these different toys, so kids' children's toys, he's really into. But he also likes just destroying things, and so the easiest and cheapest way to let him destroy things is cardboard boxes and paper balls and blankets and stuff. And so we hide his food inside those, and we'll come back the next day, and it's...The cardboard box is not just gotten into, it is ripped into a hundred little tiny pieces and scattered everywhere. So he..had fun.
Hank: He likes that *chuckles* He likes doing that.
Jessi: So that would be fun to see.
Dr. Marzluff: Why is he doing it? How is he doing it, how fast.
Jessi: Yeah, what's going on there. But as soon as we come over, he's like..."I'm not doing anything."
Hank: Right.
Dr. Marzluff: Not going to give his secrets up quickly.
Jessi: No.
Hank: Well Jessi, thanks for showing Rook off for us. Rook, thanks for coming by, goodbye.
Jessi: Yeah! I'm so...he did so good today, I was really proud of him.
Hank: He did good, yeah. And John, thank you for sharing so much
Dr. Marzluff: My pleasure.
Hank: And if people want to know more about your work and what you do, what should we read, what should we look at?
Dr. Marzluff: You can go to the website, The University of Washington - Avian Conservation Lab is my lab, and there's lots of articles there you can get, or videos and things you can see. Some books, if you're really interested in ravens, my wife and I wrote about the ravens we studied in a book called Dog Days, Raven Nights and that's kind of fun how you do science, and some of the things we learned about their behavior. And more recently I've been working on urban birds, so a book called Welcome to Subirdia is about our urban research, so you can check those out and...all sorts of neat things on the web about crows and ravens it's..lot of neat things out there.
Hank: Well thank you very much for joining us.
Dr. Marzluff: My pleasure
Hank: If you want to see more of what Jessi does, you can go to We do a show with her where it's just sort of the daily life of this person who does this crazy amazing thing in my small town. And if you want more of THIS, we are SciShow and you can go to and subscribe.

*closing music*