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.
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!
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
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
After I lay down my handful of un-shelled peanuts it’s only a matter of minutes before I can hear the “thwap!” as the steller’s jay hits the cable wire that runs above my balcony’s railing. It balances there for a moment before descending onto the pile I’ve offered it. Quickly, and with obvious purpose, it springs down the railing and picks up a nut. Its mohawk feathers bounce as it snaps and cocks its head around in various direction. After only a few seconds, I hear the sound of rejection; the distinct hollow tap as the nut is returned to the railing. The jay repeats the same process with two more nuts before abruptly flying off with one that, to my eyes, appeared identical to the first two.
Certainly most manner of corvids engage in some kind of choosy behavior though I don’t think any of them go about it with as much frenetic spunk as jays do. So the questions arise: Why are they being so picky? What do they know about the rejected nuts that my eyes can’t see?
According to a new study1, Mexican jays are actually ‘weighing’ nuts during this process. By using specialized slow motion cameras, researchers showed that those snappy head movements are actually a way for the birds to get a tactile feel for the the nut’s weight and listen to the sound the peanuts makes as it rattles in its shell. By providing nuts that were visually similar but different in mass, the researchers were able to show that jays could consistently select nuts with the most nutmeat density. A further test showed that large shells that were altered to contain only one nut were typically selected first, only be be rejected, while single nut shells were accepted. This suggests that jays either have a sense for how much nut should weigh (and thus reject nuts that contain less than they should) or that the correlation between hollow sounds and nut density lead to the ability to choose denser nuts.
So the next time your visiting jay delights you with its sassy head snaps remember; it may simply be amusing to you but for jays, it’s an impressive product of evolution that helps keep them alive.
1) Piotr G. Jablonski, Sang-im Lee, Elzbieta Fuszara, Maciej Fuszara, Choongwon Jeong, Won Young Lee. Proximate mechanisms of detecting nut properties in a wild population of Mexican Jays (Aphelocoma ultramarina). Journal of Ornithology, 2015