Category Archives: In the news

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

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

Crow curiosities: Do crows collect shiny objects?

The notion that corvids, especially magpies, have a special affinity for shiny object has been around for more than a century.  In fact to refer to someone as a magpie is to describe them as someone who ‘compulsively collects or hoards small objects’.   This idea is so old hat that it can feel a bit frivolous to even wonder if it’s true.  The trouble with this bit of corvid whimsy, however, is that when we do investigate it, and scientists have, we find there’s no empirical evidence to support it.

'Crow Collects' by Cori Lee Marvin.

‘Crow Collects’ by Cori Lee Marvin.

For instance, one study presented both captive and free-living magpies piles of blue or shiny silver screws, rings, and pieces of tin foil near piles of food to which they had been previously habituated.1  They found that, rather than thieving and subsequently caching the gleaming objects, the birds were actually more nervous to take food than they had been previously.  In the 64 conducted tests, only two instances of contact between a bird and an object were recorded.

trial

Experimental set-up for magpie study.

Cornell crow expert Kevin McGowen, elaborates on this general conclusion, suggesting that perhaps the origin of this folklore is pet crows who are attracted to the objects of obvious value to their owner like coins, keys or jewelry.  Speaking personally as someone who has spent countless hours observing hundreds of individual crows in the field, I can also attest to the fact I have never witnessed anything resembling this behavior.  So there you have it, corvids do not, according to the best empirical evidence, show an attraction to, or are otherwise known to collect shiny objects.

And yet…

And yet I still hear anecdotes about this behavior that peak my curiosity.  For instance, once or twice a year I’ll see a headline about crows thieving shiny stones at the expense of bereft family members.  In Jewish culture, it’s tradition to leave a small stone atop a gravestone, as a way to honor the deceased and indicate that they’ve been visited.  For whatever reason, particularly across Ireland, these stones occasionally go for joy rides in the mouths of crows.  In Omagh, Patsy Kerlin who mounts headstones in his town’s graveyard recently told a local reporter that “It seems to be only the black shiny ones they take and a lot of them go missing.”  Even in my own neck of the woods at the University of Washington one of the gardeners at the Urban Horticulture Center regaled John Marzluff and I with his story of how the crows regularly steal the shiny metal placards that identify the center’s plants.

In science, we often like to say “the plural of anecdote is not data”.  This is unequivocally true.  But just because they’re not data doesn’t mean they’re meaningless either.  I’m inclined to believe there’s more to these stories than random chance and I think they are worth exploring.  Perhaps these stories emerge out of confirmation bias, meaning people tend to report theft with respect to shiny things more often because they’re looking to confirm a suspicion they already had.  If so, it would be yet another fascinating example of the extent to which corvids have infiltrated our culture.  Or perhaps this is the work of curious juveniles as has been suggested by my crow colleague Dr. Jennifer Cambell-Smith.  If so, teasing out any evidence of discrimination or bias juveniles are using when selecting objects to explore could give us insight into how they learn about the world, or how our garbage is modifying that behavior.  Or perhaps crows do like to carry off with glossy objects, but for textural, rather than visual reasons.  At least some corvid species swallow small stones to aid in digestion and these stones are most often partially smoothed.2  These ‘grit stones’, however, are considerably smaller (on average only 2.9 mm) than I imagine grave stones are, so perhaps this behavior is evidence of poor grit stone selection among naive birds.

Or maybe it’s none of the above, we simply cannot say.  Which, for me, is exactly why I find these anecdotes so interesting.  While we can rule out that this behavior isn’t a manifestation of corvids’ love for bling, we can’t exactly explain this behavior either.   It’s yet another item on the shelf along with thieving golf balls and wiper blades where we can’t do much more than offer an educated guess.  So while I’m quick to clarify that crows are not attracted to shiny objects, I’m not dismissive of these anecdotes either.  My friend and colleague David Craig likes to say that every bird has a story, and citizen science is part of sharing that story.  In my book, the story of corvids and their light fingered behavior seems an ideal project for the crow minded bird nerd.

  1.  Shepard, T. V, Lea, S. E. G., and Hempel de Ibarra, N.  2014.  Thieving magpie’?  No evidence for attraction to shiny objects.  Animal Cognition 18: 393-397.
  2. Gionfriddo, J.P., and Best, L. B. 1996.  Grit-use patterns in North American birds: The influence of diet, body size and gender.  The Wilson Bulletin 108: 685-696

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Filed under Corvid mythology, Crow behavior, crow conflicts, Crow curiosities, Crow life history, Crows and humans, In the news