Kindness in an Unkindness of Ravens
Common Raven, Corvus corax, showing off at Bryce Canyon National Park, USA. Image: United States National Park Service (Public Domain)
You’d think that ravens—looking all black and bedraggled as they do, and croaking their gruff baritone croaks as they do—would be sort of, well, evil. Or at least brutally indifferent to others’ suffering. And they are! But, in a beyond-good-and-evil kind of way, they are also surprisingly sympathetic to other ravens with whom they have formed social bonds.
A new study of the Common Raven, Corvus corax, examines what are called “affiliative behaviors”—various forms of touching and preening—among ravens in the minutes after one of them has been in a fight. Researchers placed 11 ravens (raised in captivity) from four nests in a large outdoor aviary outfitted to be as natural for the birds as possible. GrrlScientist recounts:
Drs. Fraser and Bugnyar began their study by documenting the frequency of affiliative behaviors in these birds, using a standard protocol developed for primate research. They watched the aftermath of 152 fights between these juvenile ravens during the following 23-month period of time, and recorded the identities of the aggressor, the victim and the bystanders (nearby flock members), along with the intensity of the conflict (a chase flight or hitting were rated as “high intensity”, whilst a forced retreat was “low intensity”). All affiliative (“consoling”) behaviors — defined as contact sitting, preening or beak-to-beak or beak-to-body touching between the victim of the conflict and an individual flock member — were recorded during the ten minutes following each conflict. These post-conflict time periods (PC) were then matched to a control period (MC) for the same victim raven on the next possible day and the frequency and nature of the affiliative interactions that occurred in those time periods were compared….
The ravens were two to three times more likely to exhibit affiliative behaviors immediately following a conflict (the PC period) than at other, controlled times not immediately following a conflict (the MC period). And they favored those ravens they were closer to. GrrlScientist:
Basically, affiliative behaviors occurred most often when the flock member had a closer social bond with the victim raven than with the aggressor. Furthermore, the team observed an increasing probability of unsolicited bystander affiliations after more intense conflicts (when the victim was more likely to be distressed)….
“The findings of this study represent an important step towards understanding how ravens manage their social relationships and balance the costs of group-living,” Drs. Fraser and Bugnyar write. “Furthermore, they suggest that ravens may be responsive to the emotional needs of others.”
The function of the post-conflict affiliative behavior is, one must admit, not perfectly clear. But a leading hypothesis (developed in studies of chimps) contends that its function is to console: to alleviate the victim’s distress, and to do so out of empathy.
If that hypothesis is correct, it will give the lie to the (not-exactly-common) English word for an aggregation of Corvus corax, “an unkindness of ravens.” It seems these corvids just don’t want to live according to our labels.
Via GrrlScientist.
Source:
Fraser, O., & Bugnyar, T. (2010). Do Ravens Show Consolation? Responses to Distressed Others. PLoS ONE, 5 (5) DOI: 10.1371/journal.pone.0010605
Weekend Birdery: The Rook and the Pitcher
In Aesop’s fable “The Crow and the Pitcher,” a thirsty crow finds a pitcher of water and tries to drink from it, but the water level is too low to reach with its beak. So the crow drops pebbles in the pitcher, one at a time, raising the water level to the top where the crow can drink it.
A study published last August shows that rooks (relatives of crows) are able to reach the same solution as the crow in the fable. In the video below, a rook is presented with a cylinder containing a worm floating on the surface of water that is below reach of the rook’s beak. When provided with some small stones, the rook carefully drops them in the cylinder until the water level rises enough for the rook to reach the worm.
Click to watch video at youtube.
Bird brains, indeed. Via Ed Yong.
Weekend Birdbrainery: Canny Corvid Nutcrackers
A propos of last week’s birdery post, here is video of Carrion Crows in Japan using cars as nutcrackers:
From David Attenborough’s Life of Birds.
Weekend Birdery/Wordery: “Birdbrain”
I don’t think anyone actually uses the pejorative “birdbrain” anymore, but somehow we all know what it means. Maybe from children’s shows or something.
In researching this post, I’ve come to believe that “birdbrain” usage survives now solely as a cheesy trope of news, journal, and (eh hem) blog writing, where it is offered up as an illustration of colloquial folly, a straw man that the author proceeds to dispatch by adducing the latest research in avian intelligence. We at weekend wordery disdain such stale hackery.
On the other hand, we at weekend birdery are not above the occasional prose gimick when necessary. So, whether or not the existence of the term “birdbrain” implicates a widespread belief that birds are stupid, it would be a pernicious myth if it did. And any myth as pernicious as this one should be dispelled at every opportunity, even one fabricated entirely for the purpose of setting it right.
Therefore I am announcing a series of posts, beginning with this one, to illustrate just how smart birds can be. First, a caveat: For the most part, all animals—present conspecifics included—are dumb. But with that proviso, birds are not, relatively speaking, a particularly dumb class of animals. (Note: if you can conjure David Attenborough’s voice in your mind’s ear, cue it up now:) And indeed, as we’ll see over the course of this series, birds are, quite often, remarkably clever. And the cleverest of all the birds…are the corvids.
Corvids, a family that includes crows and jays (as well as rooks, ravens, and magpies), have displayed a measure of cunning that surpasses not only other birds, but also most mammals—even, in some respects, the non-human great apes. Here’s a sampling of what research and observation have taught us about corvid intelligence:
- An individual European Magpie can recognize itself in a mirror (a rare capacity for non-mammals).
- Carrion Crows in Japan have been observed dropping hard nuts in crosswalks, waiting for cars to drive over them and crack their shells. (See for yourself.)
- Ravens have exhibited the ability to tactically deceive one another in order to hoarde food or to raid each others’ stashes.
- Western Scrub Jays have demonstrated episodic memory (that is, memory of specific past events ) and the ability to plan for future contingencies based on past experience and observation. (Via Ed Yong.)
- Rooks have evinced an elementary understanding of Archimedes’ Principle, dropping rocks into a tall cylinder to raise the water level therein, so that they could reach a worm floating on the surface. (Watch it. Via Ed Yong, again.)
- Many corvids are known to use tools—for example, a stick to get a grub out of a small hole. But the New Caledonian Crow can make and modify tools (like hooks) and can even use tools to make or acquire other tools.
I’ll explore some of these studies and others in more detail in posts to follow.
A New Caledonian crow uses a stick tool to extract mealworms from a drilled log in the Oxford laboratory.
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