The Call of Relatives

Crows Can Recognize The Calls Of Relatives
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ScienceDaily (Mar. 20, 2007) — Most of us would know our mother's voice on the phone from the first syllable uttered. A recent Cornell study suggests that crows also can recognize the voices of their relatives.

By recording and analyzing the alarm caws of American crows, Jessica Yorzinski '05 found seven subtle acoustic differences in features that differed among individuals -- differences that the crows could potentially use to recognize one another's calls. She also found that female crows had higher-pitched calls than males. Yorzinski is now a graduate student at the University of California-Davis studying the mating choices of peacocks.

The recently published study suggests that this ability could be particularly important for crows because they interact with family members throughout their lives.

"Lots of crows end up breeding in the neighborhood they grew up in so there is no doubt in my mind that they recognize each other. How they do that, we have no idea," said co-author Kevin McGowan, a researcher and editor at the Cornell Lab of Ornithology who has studied the family lives of crows for 18 years.

To see if vocalizations might be a cue, Yorzinski recorded more than 10,000 alarm calls (made when she approached the birds) of 15 crows from five family groups around Ithaca that had been individually marked with tags as part of a long-term study co-authored by McGowan. She then measured more than two dozen acoustic features of a subset of these calls, including frequency, duration, bandwidth and energy distribution using a sound analysis program developed by the Lab of Ornithology's Bioacoustics Research Program.

Adapted from materials provided by Cornell University. Original article written by Pat Leonard.

Cornell University (2007, March 20).

Crows Can Recognize The Calls Of Relatives.

ScienceDaily. Retrieved January 21, 2009, from http://www.sciencedaily.com/ /releases/2007/03/070319200143.htm

The Crow Paradox

This is a transcript from NPR:

Copyright ©2009 National Public Radio®. For personal, noncommercial use only. See Terms of Use. For other uses, prior permission required.

Heard on Morning Edition

July 27, 2009 - STEVE INSKEEP, host:

Somebody may be holding a grudge against you right now and you may not even realize it. To tell us about that somebody - or rather something - we've brought in NPR science correspondent Robert Krulwich once again. Robert, welcome back to the program.

ROBERT KRULWICH: Thank you. Steve, this is kind of a puzzle. People like Professor Kevin McGowan of Cornell…

Professor KEVIN MCGOWAN (Cornell University): Yes, speaking.

KRULWICH: Hey, there. And is this Professor John Marzluff of the University of Washington?

Professor JOHN MARZLUFF (University of Washington): It is.

KRULWICH: Okay. So, both these guys have spent their adult lives studying crows. They're crow scholars.

Prof. MCGOWAN: Yes.

Prof. MARZLUFF: Yeah.

KRULWICH: Yet I am told that no matter how much you study crows, know crows and love crows, when crows get together in a crow group, you guys cannot tell one crow from another. People can't tell crows apart.

Prof. MARZLUFF: Oh, that's absolutely true.

Prof. MCGOWAN: Yes.

KRULWICH: And yet while we cannot tell one crow from another, crows can tell people apart?

Prof. MARZLUFF: Yeah, that's right. They're much better at it than we are.

Prof. MCGOWAN: We just can't do it as well as they can.

(Soundbite of birds squawking)

KRULWICH: Professor McGowan says when he handles a baby crow, which he does -he goes up to nests to band them - the little crow will look at him angrily.

Prof. MCGOWAN: Well, when you're holding them, yeah, they don't look any too happy, and they do more than just look at you. They try to bite you when they can, too. And then, of course, the baby crow starts to squawk, which sets the parents squawking and then the neighbors squawking and then the squawks attract more squawkers.

KRULWICH: Then suddenly you've got 20, maybe 30, birds screaming?

Prof. MCGOWAN: It's like they don't really know why.

KRULWICH: Now, the whole neighborhood now hates you, right?

Prof. MARZLUFF: Most of my neighbors hate me.

KRULWICH: I'm referring to the crow population.

Prof. MARZLUFF: Oh, the crows. Oh.

KRULWICH: Yeah.

Prof. MCGOWAN: Crows are extremely responsive to other crow behavior. They learn from the reactions of other crows.

KRULWICH: And here's the fascinating part: Once a crow sees another crow squawking at a person, yes, they join in automatically, but somehow they will also remember that person that they're squawking at. So, should they see you again, they're going to squawk at you again, which will warn a whole new set of crows in that next place you're a bad guy. So now you've got a whole new set of crows that have learned to hate you.

And so Professor Marzluff says that after he banded some baby crows near the University of Washington, everywhere he went across the campus, whether he went to an automatic teller at the local bank…

Prof. MARZLUFF: And if I go and play tennis in the neighborhood court, if I walked around the block, if I walk over to my neighbors, there are several individuals that will scold me, regardless of what I'm doing.

KRULWICH: And Professor McGowan says after he banded some crows near Ithaca, New York, he could be downtown, very far from any crow nest…

Prof. MCGOWAN: And a crow looks down and he sees me and starts yelling. And, I mean, I'm walking on the sidewalk.

KRULWICH: Or he could be in a public park. He could be mingling with other people, and then a bunch of crows would suddenly appear…

Prof. MCGOWAN: They would come out of the woods and circle overhead, yelling at me.

KRULWICH: No.

Prof. MCGOWAN: And you have to understand, this is a public park with - had this softball complex in, hundreds of people that came there. And, you know, you get kind of paranoid after a while, 'cause everywhere I'd go the crows would be yelling at me. And they wouldn't be yelling at other people, and you just kind of get paranoid.

(Soundbite of laughter)

Prof. MCGOWAN: And it's not just being paranoid. It's also, it's lonely being hated, you know?

(Soundbite of laughter)

KRULWICH: But I - I still don't understand how they do this to you. How do they know who you are when you don't seem to be able to know who they are?

Prof. MCGOWAN: I don't know. At this point, I don't know. Certainly, the crows can do a remarkable job at telling us apart, and we stink at telling them apart.

KRULWICH: Well, one way to get into this question, thought Professor Marzluff, is to figure out whether it's our smell or our shape or our voices, our hair. What is it about us that crows focus on? The obvious candidate is, of course, our face. So, in Seattle, Marzluff bought a mask.

Prof. MARZLUFF: I had picked a caveman mask that was readily available for 10 bucks or something.

KRULWICH: And while wearing that mask…

Prof. MARZLUFF: This extreme face…

KRULWICH: John Marzluff banded some little crows. So the crows could see the mask and learn to fear it and hate it. Then, who did he put the mask on?

(Soundbite of laughter)

Prof. MARZLUFF: That's a great question. Anybody who will wear it.

KRULWICH: He gave it to old people, young people, bald people, hairy people, female people, male people.

Ms. HEATHER CORNELL (Graduate Student, University of Washington): So they had different body sizes, different clothing.

KRULWICH: Different ages.

Ms. CORNELL: Yeah.

KRULWICH: But what they all had in common was that single, caveman face. So, with his graduate student, Heather Cornell, Marzluff asked people who had never touched a crow to walk through the campus wearing the caveman mask. And with the caveman mask, whoever was wearing it, over and over and over…

Prof. MARZLUFF: All of the time, some birds would scold whoever was wearing that caveman mask.

KRULWICH: All of the time?

Prof. MARZLUFF: All of the time.

Ms. CORNELL: So we figured they're focusing in on the facial region.

KRULWICH: It was a logical conclusion. But then how do you know for sure that it's not something about plastic or just the mask-ness? So, as a control, John bought a Vice President Cheney mask, which was never used to band crows, and then he gave the Cheney mask to people. When they wore that mask…

Prof. MARZLUFF: Well, we consistently got strong reactions from the students on campus…

(Soundbite of laughter)

KRULWICH: No, no, no, no, no, no, no. I'm just interested in crows, here.

Prof. MARZLUFF: Oh, the crows. Well, very, very low response rate - orders of magnitude lower.

KRULWICH: So the crows overwhelmingly reacted to the face that once threatened a crow - the caveman face, not the Dick Cheney face. And then maybe the strongest evidence that crows really do concentrate on faces: when John Marzluff asked some of his people to rotate the mask, to wear the caveman mask on their face upside-down, crows who passed by turned upside down to look.

Prof. MARZLUFF: They often turned their head upside down and they'd look at us when we had that mask on.

KRULWICH: (unintelligible) They were doing this in flight?

Prof. MARZLUFF: They would do it in flight, and they would still scold that face.

(Soundbite of birds squawking)

KRULWICH: So, okay. We can say that crows maybe recognize individual humans by our faces, but the question remains why. Why can they do that when we have such trouble doing it to them? Professor Marzluff says it's because crows need to know about human difference.

Prof. MARZLUFF: They have to know a good person from a bad person, because in a given neighborhood, one person might feed them and another person might shoot them - and that literally happens in my neighborhood. And so it pays for a crow to pay attention.

KRULWICH: While we people, we are not threatened or helped by individual crows, so they do need to know about us, but we don't really need to know about them individually, which may help explain why, says Professor Marzluff, they notice us but we just don't notice them.

Prof. MARZLUFF: That's right. That's a great paradox.

INSKEEP: One of the scientists who spoke with NPR science correspondent Robert Krulwich, who's still with us. And, Robert, I want to make sure I understand this. You're saying that people cannot tell crows apart, even if we try?

KRULWICH: That's what I'm saying. I could put you to the test, if you like.

INSKEEP: Okay.

KRULWICH: We have on our Web site kind of a crow line-up. Why don't you go ahead and look? And on the site, we will give you a picture of a crow, an individual crow. You can look at it, study it as long as you like. Try to familiarize yourself with that crow.

INSKEEP: That is a charming crow. You want to have this crow as a pet.

KRULWICH: Look closely at it, now.

INSKEEP: I'm looking closely.

KRULWICH: And when you're ready, click. And that same crow, your crow, will appear - it's going to be a different photo this time. But that crow will appear in a lineup of other crows. And just see if you can tell your crow from the other crows.

INSKEEP: Okay. I've got a guess. Here we go. I'm going to pick number two out of six. Correct, yes.

(Soundbite of laughter)

INSKEEP: Yes.

KRULWICH: I want the national audience to understand it's very unusual. Try it again, Steve.

INSKEEP: It says try another crow. Try another - okay. Another one. Oh, this is a tough one. This is a tough one, but I am going to pick number five. Oh, that time I was wrong.

KRULWICH: Try it again.

INSKEEP: Okay, fine. Well, I get to keep picking? I'm just picking them all.

KRULWICH: Yeah, you can keep going. Yeah.

INSKEEP: Okay. There were go, correct after four tries.

KRULWICH: And you can do this, by the way, at home, if you like. All you have to do is go to our fabulously just brand newly redesigned Web site. It's called now npr.org. It was always called that, but it's better looking.

INSKEEP: NPR science correspondent Robert Krulwich on NPR News.

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NPR transcripts are created on a rush deadline by a contractor for NPR, and accuracy and availability may vary. This text may not be in its final form and may be updated or revised in the future. Please be aware that the authoritative record of NPR's programming is the audio.

Crow Landing

From my email, from Missoula Montana, from a gentle woman who asks to remain anonymous.

Imao Keinen

Imao Keinen was born in Kyoto, 1896. He studied under Umekawa Toi, an important artist in the genre of Ukiyo.

Imao's works were shown at the Paris Exposition in 1900. He lived to be 92 years old.

Misleading Title

This raven chick isn't wild. This appears to be a rest stop or maybe a campground. It's likely he's an abandoned pet, or has become tamed in his experience scrounging from resting motorists.

Smart Crooks

Proving that crows do recognize each other, Renee Ha has observed that they use different tactics when stealing food from each other, depending on whether the dupe is a relative, neighbor, or outsider:

When the birds are related a crow will
use a passive strategy and walk up to
or kind of sidle next to the bird with
the food. Often the second bird will
give up the food to the scrounger.
With aggressive scrounging, there
is usually a flying approach by the
thief who nearly lands on the other
bird. This can be followed by vocalization,
physical contact and attempts to take the
food. Usually it also involves chasing
and avoidance by the bird with the food.

http://www.sciencedaily.com/releases/2003/03/030312071637.htm

Alien Abductions

As a man of science I do appreciate the need for study. But I cannot help but sympathize with the family of crows panicking while we kidnap their young for metrics and tagging.

http://www.birds.cornell.edu/Publications/LivingBird/spring98/crowsSp98.htm

Sedating them might be the better option, but we really aren't clear if the after-affects might not be harmful, especially for the chicks.

http://elibrary.unm.edu/sora/JFO/v062n04/p0450-p0453.html