NARRATOR: Professor John Marzluff knows that crows talk. And that is at the heart of his ground breaking new study.
JOHN MARZLUFF: See that nest up there?
NARRATOR: He wants to find out if crows have the ability to pass information on, not just from one adult to another, but from one generation to the next.
To study this he’s going to follow several crows from hatching through their first year to see how they learn. It won’t be easy. Less than 50 percent of crows survive their first year.
JOHN MARZLUFF: Right now all we know is that there’s eggs up there and it’s really a gamble whether those eggs are going to turn into young birds that we are then able to follow when they leave the nest and encounter new things in their environment.
NARRATOR: Before the eggs were laid, Marzluff and his team caught and banded adult crows in five different test locations around Seattle. They wore a different mask at each location.
Now a handful of crows at each of those test sites, including our crow parents, has learned that one specific mask means danger.
What Marzluff wants to find out is whether the parents will pass on their knowledge of the dangerous face to their young, and will the young not just learn to recognize this face but remember and use this information months from now when their parents aren’t around?
NARRATOR: Surprisingly, this kind of learning in the wild has only been proven with primates.
JOHN MARZLUFF: We’re trying to see the fledglings in this nest…
NARRATOR: When the team stands in the park without their masks on, the crows’ responses appear to be quite normal.
JOHN MARZLUFF: So those are just regular caws communicating certainly some excitement, but not a scolding vocalization.
NARRATOR: Now, as part of the experiment, he puts on the mask and it is a whole different story.
JOHN MARZLUFF: We’re in a critical part of the study right now because the young are just at the point where they are learning everything that they’re going to need to survive for this next year or two. And we want them to learn as part of this process that some people are bad, in particular our face with the mask on it is bad.
JOHN MARZLUFF: We have to show that a trait is observed, not directly experienced by an individual, which is what we are doing with these young birds as they see their parents scold the mask, then we have to see if they have learned from their parent to respond, and do they take that learning and that memory with them as they establish in a new place? That’s really the hallmark of intelligence that’ is seen in very, very few animals.
NARRATOR: At three weeks old the baby crows are almost ready to leave their nests.
JOHN MARZLUFF: Kind of a tight spot here.
NARRATOR: Now it’s the time in the experiment to put leg bands and radio tags on them. The team is ready on the ground to catch any crows who might decide to make a break for it.
JOHN MARZLUFF: All right, Dave, get ready…
DAVID CRAIG: Okay.
JOHN MARZLUFF: Get ready, Heather… There he goes Dave, right at you!
DAVID CRAIG: I’ve got him, I’ve got him… We got him!
JOHN MARZLUFF: I’m coming down…
HEATHER CORNELL: These guys are so calm.
JOHN MARZLUFF: Probably the best way to understand the development of intelligence is to follow a young bird as it’s gathering its intelligence.
DAVID CRAIG: How was your climb, John?
JOHN MARZLUFF: (laughing) either the trees are getting taller or I’m getting older, or a little of both… Really without a radio tag where you can reliably every day find that individual, see what it’s doing, compare what it did yesterday, understand its experiences for accumulating life… without that you really can’t understand its development of cognition.
NARRATOR: They band eight birds from five different nests.
JOHN MARZLUFF: There it goes… I think you got it, good job… That one’s got the White Wings, that’s awesome.
DAVID CRAIG: Oh wow! White Wing, welcome to science!
JOHN MARZLUFF: All right, we need to get these kids back to their family.
NARRATOR: The final stage of Marzluff’s experiment begins. As he walks back and forth within sight of the last crow, the subject’s reaction is one of benign indifference.
JOHN MARZLUFF: I’ll go back by with the mask on, and see if we can see any difference.
NARRATOR: As he was growing up, this young crow repeatedly saw his parents scold researchers wearing a particular mask. Now Marzluff puts that same mask on. He’s not expecting the same reaction he got with the crow’s parents. This is a young bird - naive and inexperienced, and trying to learn to cope on his own. If he makes any call at all, it would be significant. But Marzluff’s fear is he might just fly away.
For a moment it seems like he has done just that, but then the bird takes another perch higher up, keeping a close eye on Marzluff and his mask.
And then, there it is. To many, just the tentative scold of one young crow. But to John Marzluff it’s a major milestone.
JOHN MARZLUFF: That was pretty exciting. You’ll never be able to get a better exposure than that, I don’t think, that was clean. To me what it indicates is that that bird clearly recognized this face, which the only way it could have learned about this face as being anything unique was from its parents’ behaviour. So I think that shows the first step of social learning.
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