Category Archives: crow intelligence

Why the crow smiles

There’s hardly a corvid species that doesn’t strike me as beautiful but there’s only one that’s always struck me as particularly gleeful.  Looking at the New Caledonian crow it’s evident there’s something different about the shape and proportions of its bill. It’s a bit shorter and more blunt, and it lacks the obvious downward curve of a typical crow bill, with lower mandible actually curving slightly up. Put together, these features appear to give it the perpetual grin that trademarks this species.  I’ve joked that this must be because they’re always feeling very pleased with themselves for being so smart, and thanks to new research, I’ve come to learn my joke had it backwards.

By using tomography scans, Hiroshi Matsui and his team were able to compare the shape and structure of the NC crow’s bill with that of its close relatives. Their conclusion, which they report in the March issue of Scientific Reports, is that this shape makes the handling and manufacturing of tools easier. Looking at photos of the birds in action, it feels intuitive that the more exaggerated curve of a raven or American crow bill would have a hard time achieving the dexterity that NC crows need to use their stick and hook tools.

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Given this new research it’s time to amend my joke. It’s not that NC crows grin because they’re smart, they’re smart because they grin.

Literature cited

  1.  Matsui, H., Hunt, G., Oberhofer, K., Ogihara, N., McGowen, K., Mithraratne, K., Yamasaki, T., Grey, R., and Izawa, E. 2016.  Adaptive bill morphology for enhanced tool manipulation in New Caledonian crows.  Scientific Reports 6. doi:10.1038/srep22776

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Filed under Crow behavior, crow intelligence, Crow life history, New Research

I spy with my raven eye…

…someone trying to steal my lunch.  Turns out, humans are not the only ones wary of peeping Toms; new research shows raven can imagine being spied on by a competitor.

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The other day my friend and I were having a very merry time at the thrift store when, without cause or provocation, this women decides to up and ruin our trip.  Well really, she simply spotted the same gorgeous caste iron dutch oven that my friend wanted and reached it first, but the consequence was the same (it was a tragically beautiful dutch oven). This dynamic-my friend having her own intentions (to obtain and own that dutch oven for herself) and recognizing that this other women had her own intentions (to obtain and own that dutch oven for herself) is something so second nature to being human we rarely give it any thought.  But the ability to attribute mental states to those around us is an incredibly profound and complex cognitive task.  Understanding if this ability, called Theory of Mind, exists in other animals has been among our top interest as ethologists.

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Like other corvids, ravens cache food and, as a consequence, run the risk of their caches being stolen by others.  It has long been known that if ravens can see that they are being watched, they behave differently when it comes to caching than if they are alone.  This is interesting, but doesn’t necessarily speak to whether they posses theory of mind because of the confounding effect of “gaze cues”.   Basically, the correlation between head cues and competitor behavior make skeptics doubtful about non-human animals having the ability to know what others might be seeing.  So raven master Thomas Bugnyar and his colleagues Reber & Bruckner recently published an elegant study to address just this issue.

By training captive ravens to look through a peephole, and then allowing them to cache food with the peephole opened or closed, the researchers were able to show that ravens behaved as if they were being watched when they could hear ravens and the hole was open, but not when they could hear ravens but the peephole was closed.  What this suggests is that ravens are capable of remembering their own experience of looking through a peephole to see into another room, and can imagine that another bird might be doing the same thing even if they cannot see this bird.

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Experimental set up.  Bugnyar et al. 2016.  Nature Communications

Theory of mind and imagination (which are not mutually exclusive) are the cornerstones of what makes for a powerful cognitive toolkit and have long been thought to be uniquely human.  As we continue to build on the body of work showing non-human primates, corvids and some other animals posses some of the same skills we do, many will be challenged to redefine what it means to be human.  Personally, framing the question that way doesn’t interest me.  To me the more interesting question is not how are humans different from ravens, but how are we the same and why? What is it about being human and being raven that make possessing imagination important?  Fortunately there is still loads more research to be done, and when it comes to teasing out this question I can only imagine the possibilities.

Literature cited:

Bugnyar, T., Reber, S.A., and Buckner, C.  (2016) Ravens attribute visual access to unseen competitors.  Nature Communications 7.  doi:10.1038/ncomms10506

 

 

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Filed under Crow behavior, crow intelligence, New Research, Raven behavior, Raven intelligence

Meet the environmentalist crow

Having grown tired of being referred to as dirty and messy, one hooded crow in Izmir, Turkey took matters into its own beak to help make its park a little cleaner.

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For anyone that can read Turkish you can find the original story here

According to the Turkish Newspaper, Radikal, after eating the leftover rice the crow flew over and dropped the used plate in the garbage bin.  What could explain this amazing act of social and environmental prowess?  I often see crows take food wrappers or packages up to a perch and then drop them once they’ve fished out all the crumbs.  Could be that this crow was simply in the right place at the right time to turn this typical behavior into something extraordinary.  Then again ¯\_(ツ)_/¯ .  We’ll never be able to say for sure what this crow was thinking, maybe it just got tired of all those litterbug people mucking up its park!

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Filed under Crow behavior, crow intelligence, Crows and humans, Just for fun

Counting abilities of crows

Breaking news: Crows probably have sense of numerical competency (a.k.a. they can count)!  Ok, so this isn’t breaking news, and it’s not exactly true, but it makes for a nice headline as evidenced by the number of articles that have shown up in my inbox this week regarding a new study.  As early as 1950, Otto Koehler, a German animal behaviorist, showed that captive Western jackdaws would only turn over enough boxes to obtain the corresponding number of treats they saw him hide (up to around six).  Parrots too, have  shown that they can solve problems requiring the ability to count to around six1.  So what makes this new study so special?  It’s not so much that researchers showed that crows can discriminate quantities but how.

By presenting trained carrion crows with computer screens that showed two quantities of either matched, or mismatched dots, researchers were able to demonstrate that the birds could correctly indicate if the quantities were the same or different, despite the dots being of different sizes and arrangements2.  While that’s in and of itself cool and of value, the main finding what that it’s actually individual neurons that are recognizing and responding to these different quantities.

Photo: Andreas Neider

Photo: Andreas Neider

Why is that so cool?  Because that’s basically how our own brains begin to understand numbers too, despite our brains being, in some ways, really different.  Take that in for a minute: Our human brain, and a crow (a bird!), process numbers in a very similar way.  For a scientist,  the neon sign illuminating “convergent evolution” immediately lights up.  The researchers did not show, however, that that they could count in a strict sense like us, meaning the neurons were responding to numbers relative to each other and not to stand alone values. So perhaps jackdaws or carrion crows are different in this respect, or Koehler’s experiments were testing a different kind of problem solving ability that better teased this out.  Still, crows prove once again what magnificent animals they are and their relevance in understanding our own evolution as humans.

1) Pepperberg, I.M. (1999) The Alex studies: Cognitive and communicative abilities of Grey Parrots.  Cambridge, MA: Harvard University Press.

2) Helen M. D. & Andreas N. (2015) Neurons selective to the number of visual items in the corvid songbird endbrain. PNAS  DOI: 10.1073/pnas.1504245112

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Filed under crow intelligence, Crows and humans, New Research

Corvid of the month: The jungle crow

If there’s one corvid that’s most notorious for getting into trouble, it’s probably the jungle crow (sp: Corvus levaillantii genus: corvus).  A dubious reputation perhaps, but it’s one that’s been well earned through this corvid’s knack for exploiting humans and the opportunities we create.

Physical description: While jungle crows aren’t much bigger than an American crow, their square head and heavy bill gives them a more raven-like appearance.  To me, they look like what I might expect if a common raven tangoed with Rick Moranis’s contraption from Honey I Shrunk the Kids.

Range: They are found throughout the northeastern Asian seaboard to Afghanistan and eastern Iran in the west, through South and Southeast Asia, to the Lesser Sundas and Cambodia in the southeast.  Although in India the jungle crow and large-billed crow behave has two distinct species, in northern parts of Asia their distinction is less clear and colloquially the two are often analogous.

Conservation status: Given their large range, it may come as no surprise that their populations are abundant and are considered a species of least concern by the IUCN.  In fact, since the 1980’s the number of jungle crows in Tokyo has quadrupled1.

“Corvus macrohynchos map”. Licensed under CC BY-SA 3.0 via Wikimedia Commons

So what accounts for their bad reputation you ask?  Where to begin…how about vandalizing cemeteries1.  In Japan, food is left at the burial sites of loved ones as an offering.  Although in some cultures these offerings are meant to be eaten by animals, that is not the case here, and the crows’ stealing of food interrupts the intention of the ritual.  Historically, this probably wasn’t a conflict since jungle crow populations were much smaller than they are now.

As if that wasn’t enough to get people fired up, jungle crows also have a bad habit of, well, firing things up.  People were stumped how field fires near the Fushimi-Inari shrine in Kyoto were starting until someone thought to watch the crows.  There are 10,000 candle holders that line the walkways of the shrine and on busy days they may contain thousands of individual burning candles.  With some diligent watching, researchers discovered that crows were eating the melted candle wax (which is often made with tallow) and in some cases taking the burning candles out of the holders and flying off with them.  Although they never witnessed it, researchers suggested that crows’ attempts to cache burning candles may have been the cause of the mysterious fires2.

Photo: H. Higuchi

The crows appeared to show no fear of the flames according to the paper’s author. Photo: H. Higuchi

To top it all off, jungles crows seem to be just as good at turning out the lights as there are at lighting them up! Unlike American crows, which predominately use sticks to build their nests, jungle crows have developed a fascinating (and immensely frustrating for the Japanese government) habit of using clothes hangers to construct nests.  Mixing wire hangers with power lines is a recipe for disaster and in the summer time jungle crows are responsible for massive blackouts.  The Tokyo government spends millions of yen, and employs full time crews, to search for and destroy hanger nests in an effort to prevent such black-outs1.

Photo: Götz

Maybe Joan Crawford had just spent too much time around jungle crows…  Photo: Götz

It’s not all bad press for these resourceful crows, however.  One of the more spectacular things they are known for is using cars to crack open otherwise inaccessible nuts.  Not only that, but they also appear to be sensitive to crosswalk signals and know when it’s safe to collect the exposed nuts and when it’s not3.

So while the jungle crows make their fair share of trouble stealing food, candles and hangers, there are still plenty of people who adore these animals for their cleverness and ingenuity.  For those that don’t, well, some Japanese aren’t shy to take control measures into their own hands.  Or should I say mouths…

IMG_1922Literature cited:

1Marzluff, J.M. & Angell, T.  2005 In the company of crows and ravens.  Yale University Press

2Higuchi, H. Crows causing fire. (2003). Manuscript from The University of Tokyo

3Marzluff J.M & Angell, T. 2012. Gifts of the crow.  Free Press

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Filed under Corvid of the month, Crow behavior, crow conflicts, crow intelligence, Crows and humans

A scientist’s thoughts on The Crow Box

The first time I watched the writer and hacker Josua Klein’s crow vending machine TED talk as a college undergrad, I was floored.  It was my first exposure to Betty, to the capabilities of crows to manufacture tools, and the success of the vending machine filled me with ideas.  I used clips from the talk for a variety of public outreach presentations and they were always met with the same kind of GTFO amazement that I love watching people experience as they learn about crow intelligence.

Betty just doing her normal New Caledonian crow thing of making hooks out of wire to pull up buckets of food.  No big deal.  :)

Betty just doing her normal New Caledonian crow thing of making hooks out of wire to pull up buckets of food. No big deal. 🙂

As I moved on to graduate school, however, and began to be fully immersed in the scientific community of crow nerds, I started to hear rumblings that gave me some pause.  Rumblings that suggested the vending machine wasn’t all that it was cracked up to be and in fact, had not worked as it was implied in that TED talk.  Since I’ve never worked personally with Klein, I’ll let my fellow crow scientists speak for themselves on the issue.  You can find one of the graduate students he worked with relating her experience during a reddit AMA here, and as well as the correction that the New York Times Magazine was forced to run after publishing an article on Klein’s effort with the vending machine.  If you don’t want to read them, suffice it to say the main point is that Klein gave people the impression that it had been tested on zoo and wild crows when it hadn’t.

The Crow Box

The Crow Box

Leading the public to believe that we’ve arrived at conclusions when we haven’t is the stuff of stress dreams for scientists, and it’s why the peer review process is the foundation of good scientific practice.  By taking “results” that were only in the early stages of being tested and bringing them to the attention of the public without permission or support from the scientists he was working with, Klein burned his bridge to the folks who had offered to help him test the idea, and probably any other crow scientist he might approach next.

Which brings me to the recent article I read titled “This Machine Teaches Wild Crows to Bring You Coins for Peanuts.” No, it doesn’t.  It might, but probably not.  No one has been able to train wild crows to bring specific items in exchange for food, the website selling the machine even points this outGabi Mann did not intentionally train her crows to bring her things.  They did this of their own volition which is why her collection is as diverse and unique and beautiful as it is.

Gabbi showing me a sampling of her favorite gifts from the crows

Gabbi showing me a sampling of her favorite gifts from the crows

The suggestion that this machine could train crows to bring you quarters, seems to hold about as much water for me as saying you could use a dog whistle to train wild wolves to roll over on command.  The reason that the machine worked on captive birds in the Brooklyn apartment where it was originally tested is that, in captivity, you have a certain amount of leverage over an animal.  You can motivate it with food or treats or affection.  The chances that a wild crow would go to the effort of looking for coins when it could simply skip that step and look for other food seems insurmountable.

All that being said should you turn your nose up at The Crow Box if the idea intrigues you? No, go for it! Maybe yours will be the mind to figure out how to motive wild birds to participate. Or, perhaps you don’t care if it works or not, you’re just in it for a new experience or the joy of trying.  Trying and failing is part of discovery and I see no reason people should wash their hands of it if it sounds like fun.  Plus, even if it doesn’t work, you may end up learning different, but just as amazing things about these birds.  Just don’t hold it against the crows if they decide it’s simply not worth the trouble and leave it to you to go collect the quarters you lost buying The Crow Box.

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Filed under Being a scientist, Crow behavior, crow intelligence, Crows and humans

Reaching the limits of crow intelligence

When I was in college it became a joke among my friends and I that they would greet or bid me farewell with the following phrase “I believe in crow intelligence.”  Even as an undergrad, my passion for crow behavior and cognition was evident to my friends and family and I relished the emerging data demonstrating that this relative underdog was far exceeding our expectations of what an animal, especially a bird, could do.  While I still carry this phrase as a mantra in my research, it’s something I’ve also grown cautious to keep in check.  I’ll come back to this point in a minute, but for now let me rather crudely transition to some exciting new research.

The fantastic Alex Taylor and his group at Auckland University have once again dazzled us with another one of their eloquent studies on the New Caledonian crows.  This time they were looking at yet another aspect of crow’s learning intelligence: the ability to observe cause and effect and exercise a new behavioral pattern i.e causal intervention.  Essentially the researchers presented both the crows and two year old children with cylinder that, when hit with a block, would reward them with food.  The subjects were first exposed to the set up by baiting the block with food, thereby  demonstrating that, when moved in an effort to reach the bait food, the block would drop and release even more food via hitting the cylinder.  Babies quickly learned how to use an unbaited block provided in a new location to access the food hidden by the cylinder, but the crows failed to make the cause and effect connection.

The researchers were apt to point out that while this failure provides a fascinating insight into the evolution of causal reasoning, it does not negate the ways in which these animals remain exceptional in this respect as well.  Indeed, crows outperform children in some aspects of causal reasoning as demonstrated by the Aesop’s Fable experiments they conducted looking at object discrimination.

For me, it also provides one other important reminder: that crows are not feathered humans.  Reflecting on my earlier anecdote about my iconic catch phrase, something I’ve had to come to terms with as a graduate student is recognizing my own bias regarding these animals.  Occasionally, I find myself truly disappointed by results like the aforementioned one.  Perhaps it’s an all-American love for the underdog, or a hope that if only people understood how smart these animals are they would show them more respect.  Whatever the reason, an important area of growth for me has been acknowledging  my desire to continuing showing that these animals are exceptional and being aware of when or how that might be affecting my interpretation of my results.  This is indeed what it means to be a scientist.  Even when I have a my civilian hat on, accepting that crows are not simply feathered humans is, I think, an important part of truly embracing the natural world for what it is: a rich source of both diversity and overlap all of which deserve our admiration and preservation.

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Filed under Crow behavior, crow intelligence, Crow life history