No, that crow is not sharing with a mouse

I know, I know, it looks so much like that’s what’s happening.  The mouse is clearly interested; the crow walks the direction the mouse exited to, drops food, and leaves.  But rather than sharing, this is simply a coincidental intersection of two animals trying to claim what they can.

First, a little bit of background information: In animal behavior, food sharing is defined as the transfer of a defendable food item from one individual to another, or the joint use of a monopolized item.1 Obviously these definitions are both broad and somewhat subjective. Because of this, you’ll see a range in how different papers describe how common this behavior is. Some might say it occurs frequently, while others say it is rare depending on if they’re including tolerated theft, food transfers during courtship, etc. Among corvids, evidence of food sharing has been suggested in ravens, rooks, scrub-jays and northwestern crows, but it’s been most formally studied in jackdaws.

Studies on jackdaws show that donor initiated sharing is a more common behavior for that species than it is in primates (though more rare than recipient initiated sharing), sharing decreases as the birds get older, and that patterns of food sharing support both the altruism hypothesis (tit for tat) and the harassment hypothesis (take this and leave me alone!).  A key thing among all these studies is that food sharing is taking place within social groups, not with strangers and not with other species.

Given the rarity and circumstances with which this behavior has been observed, even within corvid social groups, it is exceedingly unlikely that this crow is so generously sharing with a mouse.  So how else could we explain it?

theif

The crucial moment of truth comes at the 0:58s mark.  Crows, like many other corvids, hide food for later consumption. If you’ve ever shared enough food with a crow that it constituted multiple morsels, you might have noticed this behavior.  The crow will walk or fly to a location not generally too far away and tuck the food into a tree branch, under the soil, into your gutters, etc.  Then, like clockwork, they will use some nearby debris to cover it.  In the most adorable, “Damn why don’t I have my camera!?,” moments, I’ve seen them pick pansies to cover and hide their treats.  At the 0:58sec mark you can see the crow pick up some sidewalk detritus and do exactly this.  That’s not a signal of sharing, that’s caching loud and clear.

Some of you might be wondering why, given how smart crows are, it did such a poor job, considering the mouse was so clearly watching and ready to lift it as soon as the crow walked away.  Crows are smart, and very good at some tasks, but as I’ve said before, the ability of an animal to excel at a cognitive task requires that that task in some way relates to their natural history.  American crows are not good at, or perhaps even capable of, making hook tools because, unlike New Caledonian crows, there was no available food niche which selected this behavior.  Likewise, American crows aren’t very cache protective because they don’t really need to be. There is so much food in the urban ecosystem that most crow caches will go uncollected anyway.  On the other hand, the corvids that rely more on their caches are quite sensitive to onlookers.  As for why it picked that particular spot to begin with, that was probably the closest cache location, and since the crow probably couldn’t see the mouse, there wasn’t any reason not to cache there.

One of the more elaborate explanations I’ve read falls decidedly in the opposite direction, however.  The idea is that instead of sharing, the crow is actually baiting the mouse and the sprinkling of detritus on top was meant to slow the mouse down and facilitate the kill.  While there are some birds, such as green herons, that do use bait to catch prey, this is not a consistent feature of crows’ hunting repertoire.  That said, you can find the occasional video of crows using bait much like the herons.  We can also rule out this explanation because 1) a leaf on top of a piece of bread will slow the mouse down for approximately 1/100 of a second and 2) the crow very clearly wandered away from, and lacked the focus on the food that would be required to actually catch the mouse.

So consider the food sharing crow video officially debunked.  And don’t worry, there are still plenty of videos out there that are as exactly pure and wonderful as they seem.  I’m not coming for your golden retriever.

Literature cited

  1. De Kort, S.R., Emery, N.J, and Clayton, N.S. (2005).  Food sharing in jackdaws Corvus monedula: what, why and with whom? Animal Behaviour 72: 297-304. (scroll down to see PDF of paper)

 

 

15 Comments

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15 responses to “No, that crow is not sharing with a mouse

  1. Bob Spencer

    I feed crows and ravens. They call their families to gather and share the food. Each has a particular call to assemble their family. Actually, I suspect that they share better than do humans.

  2. Beverly

    Oh, my bubble is burst! I think you’ve explained the real reasons behind the crow – caching food. Leading off your post -one query I have: what might scientifically be happening when people talk about corvids leaving “gifts” for their human feeders? Shiny objects, food, plastic other things? Thought you might know more than the lay person.

    • I think it’s an accident that gets reinforced with food, which conditions the bird to keep doing it. I think other birds could watch though and learn that the behavior is useful and try it too. No different than the crows in Japan using cars to crack nuts.

      And side note to folks who are wondering: yes crows in the states drop nuts into the road. But we haven’t shown that they intentionally time with with traffic as they were able to do in Japan.

  3. Your style of writing and sharing your knowledge are priceless.
    Love your memes also. Thank you

  4. How I wish we had your clear explanations for so many other animal behavior videos. This was a great post, so great, I sent it to my mom!

  5. Joan

    Aaaarrgh – the first video in this post now shows as “unavailable.” Drat.

  6. Vanessa

    My vote is the mouse was fed.

    I work at a bird rehabilitation facility. You’ll find in time that most of a person’s knowledge doesn’t come exclusively from literature you read but rather the direct experiences they have. Hence, many professors aren’t able to actual apply their knowledge in the real world to make a living from it directly.

    I’ve seen American Crows do some astonishing things. So to give a counterweight from experience – it’s my belief the video is exactly how it appears to be. Any application of strict rules stating that this is not possible is an interesting opinion to read and a reminder to all of us to dont always go with one source of data. The customer service agent is not always right, the nurse assessing your condition is not always right, the car mechanic is not always right, etc. To get through life you can’t limit your minds and certainly don’t ever defer a conclusion of something to another person just because of their stated credentials. Factor in their opinions and do research then go with your gut.

    For instance, in school, until recently people were taught bats were blind (they see 3 times better than humans, how wrong were they, eh?), Pluto was or wasnt a planet depending on what year you learned about it, bulls attack the color red (they attack every color equally) , Camels store water in their humps (their humps store fat for energy while their kidneys and intestines stored water), the entire Indians in America true story, and sooooo much more we all now know wasnt true.

    In this case, the author is a fantastic person with a very strong opinion based on things she has read and her own experiences. There was no ill will just a well throughout opinion. If we were to make our decisions based on credentials the Earth would still be seen as flat and half the science books which we grew up with that have would still be applicable.

    From my own experience that has seen remarkable things take place (which I dont care to share on the net especially for an opinion on what a Crow did) and my gut feeling …. that crow fed that mouse bread and its adorable.

    • Hi Vanessa, I am happy to publish your comment because, as a rule of thumb, unless people are being threatening or targeting minority groups I do not censor comments. I also have no issue or desire to debate your opinion about what’s happening in the video and thank you for the graciousness you maintained in expressing yourself. However, I cannot let your more general anti-science thesis go unremarked.

      Yes, scientists are constantly building on previous work and sometimes those knowledge gains indicate that previously held ideas no longer warrant support. This is a natural and very valuable outcome of the scientific process. For this reason it is crucial that we examine scientific conclusions for their relative level of support and apply appropriate skepticism. However, to weaponize the fact that new scientific data invites the reevaluation of previous conclusions, is to give into a way of thinking that intentionally overlooks the whole point of the scientific method and, frankly, is socially and ecologically dangerous. We need look no further than the already disastrous consequences of human-induced climate change and the fact that America’s current administration refuses to do anything about it because Trump’s gut is apparently telling him it doesn’t exist, to appreciate this. Working in wildlife rehab I imagine you have your share of experience with this as well. For example, your training suggests that in many cases babies animals are in fact still in the care of their parents and should be left alone. How frustrating if, despite your training and knowledge of wildlife in this respect, someone chose to ignore your input because their gut told them that baby deer they discovered 10 min ago probably really wants to go be bottle fed in their livingroom. Yes you may not always get it right, but your training in wildlife rehab makes you vastly more likely to get it right than an untrained person’s gut. Or are you suggesting that your experience in this field is meaningless relative to someone else’s feelings?

      I also want to unpack your various forms of “evidence” for this thesis. It always strikes me as odd when people point to overturned scientific conclusions to argue that, in fact, we should take science with a grain of salt and really what do anyone’s credentials really mean. Because these anecdotes always seems to overlook the fact these ideas weren’t overturned (for the most part) by untrained people, but by scientists. “Pluto used to be a planet! The earth used to be flat! Sickness used to be caused by the influence of the stars! Science is bogus!” If these things were consistently being overturned by non-scientists we would indeed need to seriously question the merit of the scientific process, but they are not (with some exceptions (lichens!)). So to say “If we were to make our decisions based on credentials the earth would still be flat” is to ignore that the reason we now know it is not flat is due to work of credentialed scientists. You also seem to be conflating a combination of myth and the oversimplification of grade-school teaching with actual science. If anything your examples show that someone’s credentials can mean a great deal in their ability to debunk myth. A high school science teacher may still be under the impression that a species is defined as a group of animals that reproduce exclusively with one another, but any biologist will tell you that’s not true. Your local mailperson may tell you that you shouldn’t touch that baby bird because its parents will reject it but any ornithologist (or trained wildlife rehabber) can tell you that’s not true.

      So sure, not every science drawn conclusions turns out to be the most accurate explanation. But to toss our hands up and decide that experts don’t matter is to ignore that training actually makes a great deal of difference in a person’s ability to understand a problem which they specialize in. And it makes you sound like Trump. Do you need more of a red flag than that?

  7. Roy

    I’ve seen a crow feed a squirrel in my yard in this same manner a few years back. It looks to me that the crow in the video treated the mouse as a squirrel. Squirrels always bury their food only to scoop it back up again moments later. Crows notice the squirrels doing it every day all day long all their life.

    I witnessed a squirrel hesitant to go after a nut running half way back and forth but my dog was in the back. The crow saw the squirrel do the dance about half a dozen times then picked up a nut and flew back next to the squirrels tree then buried the nut then flew back. Squirrel came down and took the nut. Just because someone says birds can’t do that don’t mean their explanation is true.

    • Hi Roy. So this distinction may seem trivial to you but I’m going to put it out there anyway: I never said these birds *can’t* do this. In fact I made it clear at the beginning that there are a variety of circumstances where they do. My point is that it’s not what’s going on in this video based on the visual evidence at hand, and sharing with mice likely doesn’t happen otherwise based on what we know generally about crow behavior.

  8. Jon

    I agree with Vanessa and Roy.

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