Butts for nuts: can crows do our dirty work (and should they)?


It’s no mystery that garbage is one of the most pervasive issues of our time. From oceanic microtrash to seeping landfills, people are trying to work out how to address the world’s garbage crisis with increasingly grand ideas. Corvids have long been associated with garbage, sometimes acting as agents of litter themselves, but one such idea asks if they might offer a solution.

A Swedish start up, Corvid Cleaning, is attempting to train corvids to pick up cigarette butts in exchange for food, as a means of combating the pervasive litter problem across their city. They plan do this through a machine that according to their website, they’ve already successfully ground tested with wild birds.

So, will this work and is it a good idea? In my opinion no and no, for many reasons. This whole idea rests on the premise that corvids are smart, (which they are,) but being smart and being motivated are very different. It’s not an issue of whether crows *can* learn it, but how you keep them engaged over time (the company hopes to save 75% of the city’s current cigarette clean-up costs). Having fed a lot of crows a lot of peanuts, I can tell you that the appeal of unlimited peanuts wanes drastically over time. While there might be an initial rash of participants, or at least a couple highly exuberant ones, there’s a serious question of meaningful sustainability without the introduction of a more desirable (and more expensive) food.

My skepticism here is born both from my experience with crows and the cold hard fact that this has simply never worked before. This isn’t the first time someone has tried this, but the 4th. The first was in 2008, when Joshua Klein delivered his infamous and highly misleading crow vending machine TED Talk. From there the Klein team debuted their Open Source idea for the Crow Box, a build it yourself machine that offered the chance to train wild crows to exchange found coins for food. While the no promises, DIY, community science nature of the project gets a more sound endorsement from me, to date, no one has had success with the final stage of the training process. The idea it seems, makes no cents. Next, in 2017, a Dutch start up called Crowded Cities pitched the exact same idea as Corvid Cleaning, though I assume their proprietary machine was a bit different. By December 2018 though, they tabled the idea, citing a lack of resources and an inability to, “get a clear picture of what the effects would be on crows and the environment.” That same year a French theme park, Puy du Fou, hired a falconer to train some captive rooks to pick up garbage as a stunt for the park. In that case it worked marvelously but of course the stakes are entirely different between wild and captive birds. And in between all those highly profiled efforts have most certainly been the odd successful backyard tinkerer. But what eventually plays out over and over again is that while wild crows can learn to do this, no one has ever been able to scale their success into something meaningful. And I don’t think they ever will.

For a moment though, let’s say that my skepticism here is invalidated; various corvids do consistently use the machine as intended. In fact, their intelligence and understanding of cause and effect renders them quite simply excellent at it. Without the appreciation for the purpose of their activities (cleaning up garbage) the project is liable to create two different kinds of cheaters: those that steal the food out from under the participants and those that resort to collecting their currency straight from the source, before it’s officially become garbage. I’m not sure how likely either of those two scenarios are, and in fact bearing that out is nearly worth keeping quiet and bagging this whole article simply to find out. But there remains at least one more point that compels me to keep going: I have never once seen a proponent of this idea fully tackle the very real health and safety issue at stake here.  

At the smaller end of this question are the issues associated with the maintenance of the machine itself. How do they plan to keep pests and mildew out of the food hopper? Rats would be the most conspicuous problem, but it’s the smaller stuff that might prove the most challenging. In my own hard learned lesson on this, I’ll never forgive myself for infesting my sister’s kitchen with pantry months after leaving behind a forgotten bag of peanuts. And of course like any high calorie food, nuts are liable to spoil especially when unsealed and exposed to the environment. I don’t offer this in denial of the absolutely horrendous things I’ve seen crows gleefully eat, but if you are intentionally creating a crow cafeteria you have a higher obligation to the food you are serving. Especially if you offer on your website that, “Chances are pretty good that it’s possible to put the birds on a better diet and improve their overall health with this solution.”

Which brings us now to the most obvious issue: cigarettes are toxic. For example, direct ingestion of nicotine at a concentration of 0.054ml/kg causes rapid death in birds.1 While there’s no way a crow would ingest that much nicotine simply from handling a cigarette butt (even with its mouth), there’s urgent need to understand how repeated handling of cigarette filters might impact these wild animals. And truth be told, I have very little confidence that the people behind these butts for nuts ideas understand the challenges of executing that study, though I would welcome their inquiries.

Earlier I asked two questions: will this work and is it a good idea. I suspect that every iteration of person that has come up with this idea genuinely appreciates corvids for their intelligence, is concerned with the amount of litter created by people, and believes that they’ve hit on an idea that will solve a problem that needs solving. Where I think they go wrong, however, is condensing my question into a single query where whether or not it’s a good idea is simply an artifact of whether or not the idea works. It’s the Silicon Valley mindset applied to wildlife. Ian Malcom warned us against this, and here we are ignoring him yet again.

Which leads to me to what I think is the only good idea that might arise out of a machine that trades treats for garbage. Rather than exploiting wildlife, why not use the money and creativity being invested here to better train people? After all, humans like a good reward-based dopamine hit as much as the next animal. What’s the smallest amount of money that would encourage someone to dispose of their cigarette waste? That’s the start-up I’d rather see. Or better yet, pay people living wages to act as care takers for our communal spaces. Some problems don’t need a grand solution, they simply need our humanity.

Literature cited

  1. Ridpath MG, Thearle RJP, McCowan D, and Jones, F.J.S. 1960. Experiments on the value of stupefying and lethal substances in the control of harmful birds. Annals of Applied Biology 49: 77-101


Filed under Corvid health, Crow behavior, crow diet, Crows and humans, In the news, Science

17 responses to “Butts for nuts: can crows do our dirty work (and should they)?

  1. Karen Davis

    The first thing I thought was “we’d be poisoning the crows to have them clean up our mess”. In every way that is so wrong. These are fellow beings on the planet, there is nothing even remotely ok about that! Luckily I suspect they are far too smart to be tricked into it.

  2. draco18s

    “Or better yet, pay people living wages…”

  3. I think I will stop telling my residents that crows will trade coins for peanuts. I am aware that I am trading one story for another, but in the end, that’s what we all do. I tell them that, as well.

  4. Yup, humans and tobacco companies created the problem. How about a vending machine
    Filled with after cigarette Mints paid for by cigarette companies, traded for a butt?

  5. chris shank

    As was mentioned, captive crows will work daily for reinforcement, if trained properly. Examples abound in bird shows where crows have been trained to pick up trash on stage and but it in a bin. Wild, free living crows can be trained to do the same, but they have a whole world of other positive reinforcements at their wing tips that will draw them away from consistently picking up butts.

  6. bill betts

    Excellent article, as always. Alas it would be easier to train wild corvids to preform this task than to train smokers not to litter!

  7. Stacy Noonan

    1) Easiest solution is DON’T LITTER, PEOPLE!
    2) Crows aren’t this subservient

  8. Mary

    Their idea is absolutely cringeworthy. How about preventing cigarette purchases to anyone who doesn’t return 90% of their butts? Innovation will occur. Addicts are motivated. Then our beautiful wildlife will not risk burns from butts or cancer. The same beaks that feed their babies should not be encouraged to handle cigarettes.

  9. helena jones

    Brilliant article and like your research. Spot on re why ever should the birds be exposed to a toxic substance.i live n Germany where butts litter the streets yet bins are every meter is a bin . So no reason to simply drop .I enjoy the company and filming crows .They deserve better than this .Let humans take trash to a bin or pay someone to .

  10. Jasmine A.

    My concern was for the crows health too.

    If it was simply bits if paper, tha’s cute, but cigarettes have so many chemicals! The crows won’t know any better.

    Although a Cinderella-style way to clean up seems sublime, I didn’t see the blue-dressed lady asking her bird friends to die for her.

    The irony here is that they want to pay someone peanuts to do the job. I think that speaks volumes.

  11. As someone who made a 30 year career in tech, I couldn’t agree more. Tech gets away with “engineering” a solution under the premise that it will actually save money and solve a problem. In this case, as you pointed out, the solution fails on two levels: it doesn’t “pen out” and actually creates an obvious new problem. I think you were polite. This is simply a stupid idea. Perhaps, build a drone that flies up and zaps the person dropping the cigarette butt 😉 Just kidding…evolution already packed us full of sensors and motor-controls to solve this problem with a recyclable, low-cost machine: us. The question is whether evolution built a great machine with a few flaws in the command center.

  12. Great post and service to folx like me who will be getting a smaller amount of the “what do you think about this amazing story!” – I think the measure for the mutualism that the speculators want to create might be measured against the honeyguide-human mutualism (https://nature.berkeley.edu/garbelottoat/?p=1294). …” with the awesome Latin name, Indicator indicator.”

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  16. John Kehoe

    Wow. You’re very knowledgeable and interesting in your perspective, but..jeez…buzz kill much?

    It seems the biggest issue is food quality. Peanuts are cheap and it seems the main goal is “cheap labor”. But, I think providing whatever food is necessary to keep them interested is worth it for the benefit of the public interacting with nature. A sense of symbiosis. We spend public funds on less worthy things than that.
    What say you?

    • I think I made my general feeling pretty clear. Even if you could get it to work, I don’t find it to be a particularly good idea. I certainly don’t think we should be relying on exploitation as the mechanism for connecting people with nature. Plus, ideally even if it did work…what public interaction would there be? The whole premise was taking advantage of crows existing and doing what they normally do in public spaces. Maybe some person sees a trained crow and thinks, “wow these birds are a lot smarter/more interesting than I thought, I’ll learn more about them” but, for the reasons I weighed out, that benefit is not outweighed by the cost. If cities want to spend public funds connecting people to with nature there are better options.

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