The Magpie in the Mirror

ResearchBlogging.orgA typical adult human recognizes that the image one sees in a mirror is oneself. We do not know how much training a mirror-naive adult requires to do this, but we think very little.

When a typical adult macaque (a species of monkey) looks in the mirror, it sees another monkey. Typical adult male macaques stuck in a cage with a mirror will treat the image as a fellow adult male macaque until you take the mirror out of the cage.

(Experiments that attempt to determine if an individual can recognize themselves in the mirror ultimately derive from what is known as the Gallup Test, after Gordon Gallup, who first painted spots on the foreheads of primates to see which individuals .. of which species … figure out that you can inspect one’s own forehead by looking at one’s face in the mirror.)

A typical adult chimpanzee will be startled by the mirror on first encountering it, or show curiosity, maybe exhibit bewilderment. But within a very short period of time, the chimpanzee will realize that this is an image of self.

A chimpanzee that understands that this is an image of self will use the mirror to inspect his or her own body, to see things never seen before, will identify bits of lint or paint stuck to the face and groom them away, and so on. Placed with a group of mirror-naive chimpanzees, the chimp that understands mirrors already may try to freak out the other chimps by showing it the mirror. They seem to get a kick out of this.

Magpies do this too.

Well, the magpies don’t try to freak each other out, but they do “get” mirrors, according to a study recently published in PLoS Biology (Mirror-Induced Behavior in the Magpie (Pica pica): Evidence of Self-Recognition) From the author’s summary:

A crucial step in the emergence of self-recognition is the understanding that one’s own mirror reflection does not represent another individual but oneself. In nonhuman species and in children, the “mark test” has been used as an indicator of self-recognition. In these experiments, subjects are placed in front of a mirror and provided with a mark that cannot be seen directly but is visible in the mirror. Mirror self-recognition has been shown in apes and, recently, in dolphins and elephants. Although experimental evidence in nonmammalian species has been lacking, some birds from the corvid family show skill in tasks that require perspective taking, a likely prerequisite for the occurrence of mirror self-recognition. Using the mark test, we obtained evidence for mirror self-recognition in the European Magpie, Pica pica. This finding shows that elaborate cognitive skills arose independently in corvids and primates, taxonomic groups with an evolutionary history that diverged about 300 million years ago. It further proves that the neocortex is not a prerequisite for self-recognition.


(A) Attempt to reach the mark with the beak; (B) touching the mark area with the foot; (C) touching the breast region outside the marked area; (D) touching other parts of the body. Behaviors (A) and (B) entered the analysis as mark-directed behavior; behaviors (C) and (D) and similar actions towards other parts of the body were considered self-directed, but not related to the mark.

Self recognition is known in the apes and not generally in primates. However, it is ascent in very young human children (and probably all very young apes) and present in at least one species of non-ape primate (the black and white tamarin, a sort of New World monkey).
It is seen in elephants, and now it is seen in magpies.

What do these animals all share? Well, not a neo-cortex, exactly, so that may not be the “seat of self recognition” … All these creatures seem ‘smart’ but so do some other species that don’t seen to be able to do this. All are good at problem solving.

There is probably not a single clear and simple link between this ability and the cognitive capacities of any organism that has it. Mirrors do not occur in nature, so this test is measuring something in an abstract and arbitrary way. Therefore, even though we can divide the world of animals (vertebrates, really) into those that recognize themselves in the mirror vs not, we are not really dividing these species into those with a particular trait versus not. Passing (or not) this test does not indicate a particular trait, necessarily . It indicates something, but the test should be presumed to be insensitive to the specific nuances that would separate, for instance, bird from monkey or elephant from ape.

Clearly, this needs to be tested in more bird species..

Prior, H., Schwarz, A., Güntürkün, O., de Waal, F. (2008). Mirror-Induced Behavior in the Magpie (Pica pica): Evidence of Self-Recognition. PLoS Biology, 6(8), e202. DOI: 10.1371/journal.pbio.0060202


  1. #1 Jp
    August 20, 2008

    Very interesting, thanks. One note though: while mirrors themselves may not occur in nature, (i dunno, do they?) reflections do, and isn’t that the important thing here, recognizing one’s reflection, mirror or no mirror?

  2. #2 Greg Laden
    August 20, 2008

    Reflections (and shadows, for that matter) do occur in nature. One wonders what the male macaque (in the wild) thinks when it stares directly into the eye (which itself is an aggressive act) of a rival, up close, and sees an angry looking itty bitty macaque in the rival’s eye.

    But it can be safely said that elephants, primates, these magpies, etc. are not interacting with mirrors or natural reflections in some way or with a frequency that would select for self recognition in the mirror behavior. The behavior that emerges here in the lab is not reflecting any behavior that occurs in the wild, directly.

    (Sorry for the pun.)

  3. #3 Stephanie Z
    August 20, 2008

    One of the things I noted when the crow tool use information came out was that crows have, essentially, extended childhoods, like humans. I was speculating at the time that this suggested one extreme of the instinctual behavior/social learning spectrum and that this might be important for that kind of problem solving.

    It strikes me now that a strong sense of self could be very useful for social learning (or perhaps vice versa). Any thoughts about how the other animals that “pass” this test rate on social learning and/or extended childhoods?

  4. #4 oldcola
    August 20, 2008

    While reading the paper I was wondering what kind of reflective surfaces they can encounter in the wild.
    Water mirrors are quite common and always available after a rain, especially if there are almost flat dark surfaces around. For a bird standing near them, more efficient when the sun is relatively ‘low’.
    Now, next experiments could be with horizontal mirrors.

  5. #5 Zach Miller
    August 20, 2008

    What I thought was most interesting is that not all of the magpies (nor all of the chimps) presented with a mirror recognized the reflection as itself. Two of the magpies reacted as though the reflection was another bird. According to the paper, many tested apes fail to recognize that the mirror image is a reflection of self, as well.

    So, to me, not only is the potential to recognize one’s self in a mirror specialized among species, but among individuals within the species.

  6. #6 Mark P
    August 20, 2008

    It is interesting. I have wondered what some other animals, like dogs and cats, think of mirrors, but in my observations of our pets, the general rule is that they ignore them. The one exception was a dog who became very uncomfortable when shown a reflection of herself and me in a mirror. She looked away and refused to look back. She was not a shy dog, so I don’t think that would have been her reaction if she had identified her reflection as another dog. However, I suspect it had something to do with identifying my reflection as “me” somehow, while I was also directly by her side. I think it caused cognitive dissonance. But that’s just my take on it.

  7. #7 travc
    August 20, 2008

    Yeah, individual trait that has different occurrence levels between species (not 0|1). But Stephanie Z hits the most interesting point IMO.

    I suspect recognition of self to be highly related to the ability to cognitively model other individual’s perspectives. This ability should be of great advantage for social learners.

    So what is the current hierarchy of vertebrate social ‘intelligence’? Primate, Aves, Cetacean, Rodent? However you order it, it is useful to have the Aves out-group in there.

  8. #8 Mark P
    August 20, 2008

    Trave – social learners … hmm. Dogs are highly social animals. I have serious doubts that dogs can recognize themselves in a mirror, but it’s still an interesting idea.

  9. #9 Stephanie Z
    August 20, 2008

    Mark, I’m not talking about animals that stay in social groups. I’m talking about animals with delayed maturity and independence, animals that can’t survive outside the family structure until relatively late in life because they don’t operate as much on instinct.

    Crows, for example, stay with their parents for three to four years before forming their own families. Compare that to a turtle that hatches from an egg with no parent in sight and heads straight for the water. I wouldn’t expect the turtle to display much flexibility of behavior, because it all has to be hard coded.

    Dogs do something a bit different, probably related to survival in a pack. It isn’t unusual to find a younger dog in a household that seems well trained until the older dog dies. At that point, one discovers that the younger dog had just been doing what the older dog did and now has no idea what to do. It hasn’t actually learned the rules of the behavior it was producing.

  10. #10 Alioth
    August 21, 2008

    Do you have a reference for the mirror-knowledgeable chimpanzees getting a kick out of showing the mirror to mirror-naive chimps? I think that’d be an interesting paper to read 🙂

  11. #11 Matty Smith
    August 21, 2008

    “I have wondered what some other animals, like dogs and cats, think of mirrors, but in my observations of our pets, the general rule is that they ignore them.”

    I understood that the Gallup Test was not suited to dogs’ to the constraints in their vision (colour-blindness, poor resolution, possibly poor depth perception).

  12. #12 Matty Smith
    August 21, 2008

    Ugh, I’ll post that again in English:

    “I have wondered what some other animals, like dogs and cats, think of mirrors, but in my observations of our pets, the general rule is that they ignore them.”

    I understood that the Gallup Test was not suited to dogs due to constraints in their vision (colour-blindness, poor resolution, possibly poor depth perception).

  13. #13 Andrea M
    August 21, 2008

    My cast seems to ignore mirrors too. I have always wondered wether this is because it does not see the reflected image properly or because it recognises that the image is its own reflection. One thing is for sure, it cannot be that she sees the image as another cat, since that would result in a rather noisy hissing and growling session, since my cat is definitely not sociable.
    Does anyone have any idea of which of the two hypoteses might be correct?

  14. #14 dmk
    August 21, 2008

    I am sure my cat understood mirrors. She used to enjoy sitting with me while I was combing my hair. She would sit on my shoulder or next to the sink, and alternate between watching me in the mirror and drinking from the faucet. The bathroom mirror was large, and reflected a view of the outside. If a bird flew by the bedroom window and was reflected in the mirror, my cat would quickly turn around to look outside.

  15. #15 greg laden
    August 21, 2008

    Alioth: regarding chimps freaking each other out…. No paper, just eye witness accounts. It may be on a video in a special on chimps as well.

    If a bird flew by the bedroom window and was reflected in the mirror, my cat would quickly turn around to look outside.

    I’ve observed similar things. Interesting, but irrelevant the way that experimental behavioral psychology works. But interesting.

    The thing is, that overall, while domestic animals are interesting (and relevant) we are not going to advance our thinking on evolved psychology and brain function by studying them as though they were NOT some kind of extended human phenotype (in nor than small part)

  16. #16 Jon
    August 21, 2008

    I wonder if they didn’t account for all scenarios.

    For instance, when you’re talking to a friend and you see a bit of chive in their teeth, you usually point to your own teeth to show them where it is. I wonder if these magpies are doing something similar. Clearly at least one of the magpies thought the mirror reflection was another magpie (it acted aggressively toward the mirror).

    Is there an effective way to control for this situation? Video, puppets, a second magpie? Or am I just being too skeptical here? 🙂

    I agree with a previous commentor, though. They should try horizontal mirrors, if not pools of still water, and see what happens. This may very well be a behavior they exhibit in the wild. Of course, not all of the birds responded as well to the mirror. So it could possibly be a socially inherited behavior, in which case they should test the parents as well. Or it could be that the mirror is simply *too* reflective for some of the birds. They might want to test the mirror-shy magpies on less reflective surfaces.

  17. #17 jvance
    August 21, 2008

    “If a bird flew by the bedroom window and was reflected in the mirror, my cat would quickly turn around to look outside.”

    “I’ve observed similar things. Interesting, but irrelevant the way that experimental behavioral psychology works. But interesting.”

    Irrelevant? I remember, in reading about a macaque/mirror experiment, that one of the behaviors noted by the researchers was that the macaques DID seem to recognize that the reflection of a researcher wasn’t the real thing. When they saw a human enter their room in the mirror, the immediately turned around to see real thing, even though they never stopped seeing their own reflections as another, real, macaque.

    That is pretty interesting, especially since so few mirror experiments that I’ve seen investigate the subjects reactions to the reflections of others. This seems like a good way to distinguish between (A) a real lack of self-recognition, and (B)a simple lack of interest in purely visual phenomenon.

    My dog may not have much self-recognition, but I suspect her indifference to mirrors has more to do with the way she prioritizes the input from her various senses. An image with no attendant noises or odors may not seem any more substantial or interesting than the shadow of a waving tree branch.

  18. #18 greg laden
    August 21, 2008

    Yes, irrelevant. The incident you describe is anecdotal. If you really want to know, you ‘ve really got to do the experiment and really control for other things.

    There is a story that koko the gorilla repeatedly failed the mirror test. Then one day while being led form the testing site back to her enclosure, walking past a mirror, she stopped, looked in the mirror, and fixed something amiss with her fur. Self inspection with mirror. That was before any gorilla had passed the Gallup test.

    The result was not to assume that gorillas pass the gallup test. That did not happen until an actual gorilla passed the gallup test in an actual test situation.

    This is frustrating sometimes but it is how it must be done.

    Plus, again, domestic animals are … domesticated. That matters.

  19. #19 jvance
    August 21, 2008

    “Yes, irrelevant. The incident you describe is anecdotal. If you really want to know, you ‘ve really got to do the experiment and really control for other things.”

    Yes, of course: anecdotal information, as is, isn’t useful–I thought you were saying that the phenomenon ITSELF was scientifically irrelevant, which I guess you agree it isn’t: it just has to be systematically experimented with.

    And certainly domestication matters, but if a test is passed, it’s passed, no matter by what species. I’m sure that dealing with domesticated animals in tests calls for special considerations–you don’t want exaggerated results for domestics simply because they’re more comfortable around the human experimenters, or in man-made environments. But I don’t see why these factors can’t be effectively taken into account, similarly to the way you’d have to take the differences between two wild species into account. Trying to figure out if a cuttlefish and a coyote share some particular mental ability is very different, but, I would suspect, much harder than doing the same with a coyote and a beagle.

  20. #20 Stephanie Z
    August 21, 2008

    jvance, Greg’s full comment on pets, etc. was:

    The thing is, that overall, while domestic animals are interesting (and relevant) we are not going to advance our thinking on evolved psychology and brain function by studying them as though they were NOT some kind of extended human phenotype

    He’s not saying that they’re not worth studying, but (I think) that they won’t tell us the same things wild animals will about how this kind of behavior came to be in the first place.

  21. #21 xavier
    August 21, 2008

    In the anecdotal situation, the animal has not passed the test, because one cannot rule out other explanations. When the monkey turns around because “it sees someone in the mirror” how do you rule out that the cue was not sound? You can’t really rule it out even if you were there and have the strong impression otherwise. The experiment must be controlled properly.

  22. #22 Paul Burnett
    August 24, 2008

    I’m surprised that nobody has mentioned that window reflections kill millions of birds each year – see, for instance,

    (Google “reflections kill birds” and you get 258,000 hits.)

    It is common knowledge (but possibly not the subject of an experiment, so therefore obviously false – right, Greg? [grin]) that male birds will attack their reflections in a window, sometimes beating themselves to death.

  23. #23 greg laden
    August 24, 2008

    Paul, I never heard of male birds beating themselves to death (though I’m not surprised . Sounds like TMB to me), but I did just attend (Wed) a talk by a student in our program that touched on a study being done to look at bird windowstrikes.

    If mirrors (natural) were part of the cognitive reality of some bird species, you might expect that particular species to ‘get’ these windows and not run into them. This could be reflected in the window strike data.

    However, it won’t be. The truth is that a) window strikes by birds is not about ‘getting’ mirrors. Humans do the same exact thing (running into windows) all the time, whenever the opportunity presents itself. If you go to a party where there are a lot of people unfamiliar with the environment, and one of those sliding doors is closed across two spaces in play at this party, and the light is just right, someone WILL run into the window. I love watching for this and although I don’t like those films, e.g., on AFV, of this sort of thing, for some reason I can’t stop myself from watching and generally enjoying this live action. I love that commercial with the birds watching the homeowner walk into the window.

    B) Bird window strike data, it turns out, is horrid data (or at least so it seems). As a whole, there is not enough per species or per location to say much given the great number of variables involved. Which is too bad.

  24. #24 Paul Burnett
    August 24, 2008

    There’s an interesting graph at showing estimated annual bird mortality – the data for window strikes is striking.

    “Birds can see their reflection in a window. During the breeding season, when the birds are most territorial, they view the reflection as another bird intruding on their territory, and try to chase it away. Most species do not recognize the reflection as their own self.” –

    “This cardinal has been attacking the back patio door all day long (see photo!). …it was explained to me by the guy who delivers meat and dessert products to my door: Cardinals are territorial and this one has probably seen his reflection in the window and thought it was another cardinal. To which my response was: That’s a pretty dumb bird. But, I don’t know. Maybe it’s getting some sort of birdie satisfaction out of it. I know the cats have been fascinated by the show.” –

    “During breeding season, male cardinals, woodpeckers and mockingbirds may “fight” their own reflections in windows (and car mirrors). They’ll stop banging into the window as the breeding season ends.” –

    “Whap! Whap! Tick-tick-tick-tick. A number of folks are hearing such sounds this year, and when they find the source of the sound, it is a bird attacking a window. And the fool bird keeps coming back, attacking the glass for thirty minutes straight. It is two o’clock and it is time for the mockingbird, a homeowner tells a mystified guest. And lo, right on time, here comes the bird.” – (long essay on birds and mirrors)

    “Cardinals fight with themselves in mirrors,” she said. –

    “Frequently cardinals, robins and other species will spend hours fluttering up against windows or other reflective surfaces, such as shiny chrome hubcaps. This phenomenon occurs in the spring and summer. The birds are attacking their own images. At such times of year the male birds are very territorial. The birds instinctively seek to protect their nesting territories from intruders. The sight of their reflected image, even if it is a distorted image, will sometimes trigger an instinctive response.” –

  25. #25 Encefalus
    August 27, 2008

    Very interesting article. What is most interesting, however, are implications it can have on the study of consciousness. If you are interested take a look at my article

  26. #26 PengieP
    November 11, 2008

    I wonder if any experiment along these lines has been done with Octopuses.

  27. #27 Sunil Mehra
    April 26, 2010

    Recently a magpie has taken to flying onto the windowsills of one our bedrooms in which the wall paper is green and as black birds have flown into the windows of this bedroom quite often we first thought the magpie was just confusing it to be greenery of a garden. However it keeps returning to the windows and display mating rituals including mating sounds, even tapping on the glass a couple of times in succession as if knocking. Last few days it has started doing this on the windows all around the house and even around the freestandng conservatory. The conservatory glass on one side and the glass in the windows of the house are parallel to each other and it has now taken to alternating between the conservatory and the house windows. The behaviour is amusing one one hand but annong on the other as the glass is now being scratched in few places. Can anyone suggest a way of preventing the magpie from doing this? It may even form a very good subject for understandng the mirror phenomenon being discussed.