Wild Neighbors: Corvid Minds—Know Yourself, Know Your Enemy

By Joe Eaton
Thursday September 11, 2008 - 10:01:00 AM
A yellow-billed magpie, so far untested in the lab.
Ron Sullivan
A yellow-billed magpie, so far untested in the lab.

The corvid family continues to surprise. The remarkable cognitive abilities of these birds—ravens, crows, jays, and kin—have been well documented. The Clark’s nutcracker, a jaylike bird, stores thousands of pine-nut caches each fall and is able to relocate them under a blanket of winter snow. Ravens use insight rather than trial-and-error to retrieve chunks of salami dangling from strings. New Caledonian crows fashion leaves into tools to probe rotting wood for tasty grubs. Steller’s jays have been observed brandishing pointed sticks as weapons. 

Now there are reports of a bird that can recognize its own image in a mirror. And it’s a corvid, of course; apologies to the parrots. 

The mark test is supposed to be a hallmark of self-awareness, a trait we humans shared with (up to now) an elite group of fellow mammals. Researchers paint or attach a colored mark on the forehead of the subject, then show it its mirrored reflection. If the animal touches the spot on its own head, it is presumably identifying the creature in the mirror as itself. Chimpanzees, bonobos, and orangutans do this; monkeys don’t. (Results with gorillas and gibbons were inconclusive). Self-recognition has also been claimed for bottle-nosed dolphins and Asian elephants, although I’m not sure how the dolphins managed to touch their foreheads. 

It was only recently that anyone tried this with a bird. A team led by Helmut Prior at Goethe University in Frankfurt decided to work with Eurasian magpies, black-and-white corvids very similar to California’s endemic yellow-billed magpie. (Magpie taxonomy is in flux. The North American and Eurasian black-billed magpies are now considered distinct species, and the yellow-billed may be a subspecies of the North American black-billed.) 

In the initial exposure to their reflections, some of the lab magpies seemed uninterested. Others threatened their mirror images, and one male, Harvey, tried to court his. The researchers then attached red or yellow marks to the magpies’ black chest feathers and presented them with the mirror again.  

Responses were mixed, but two females, Gerti and Goldie, pecked at the mark on their own bodies or touched it with a foot, as if to say “What the hell is this?” None touched the mark in the mirror. Birds that received a black mark, invisible against their feathers, didn’t react to it. “Altogether,” concluded Prior and his colleagues, “results show that magpies are capable of understanding that a mirror image belongs to their own body.” That would put them on our side of what the researchers call “the cognitive Rubicon.” 

Self-recognition in apes, dolphins, and elephants had been credited to a part of the mammalian brain called the neocortex. But avian brains lack this structure. Somehow, magpies have evolved a parallel mental mechanism, just as birds and bats separately evolved the ability to fly.  

Meanwhile, biologists in Seattle have been running their own behavioral experiments with American crows. The results seem to show that crows can recognize individual human faces, and are prone to hold grudges.  

John Marzluff, a biologist at the University of Washington, assigned two groups of his students to wear masks in the presence of a population of crows. Students with what is described as a caveman mask trapped, banded, and otherwise annoyed the crows. (I have to assume this was a caveman of the Neanderthal persuasion, not a Cro-Magnon.) The other students, who just hung out among the crows, wore a Dick Cheney mask. 

Now if these birds were truly intelligent, you would expect them to single out the wearers of the Cheney mask for abuse. In fact, they concentrated their fire on the caveman mask. At one point Marzluff walked across campus with his cave face on and was scolded by 47 of the 53 crows he encountered—far more than the victims or witnesses of the original trapping exercise, as if word had gotten around. 

Marzluff repeated the study with more realistic masks, representing neither primitive hominids nor the vice president. Again, the crows chose to harass the mask that they associated with capture and banding. Interestingly, Seattle crows, not accustomed to being shot at, swooped close to the mask-wearers, while rural crows cursed them from a safe distance. 

In a way, this is less impressive than Gerti the magpie recognizing herself in the mirror. Other birds, including the relatively thick western gull, have displayed similar abilities to remember individual human faces. You can see the advantage for corvids, though. These are highly social birds, involved in a complex set of relationships with family members, neighbors, and occasional roostmates. It would pay to be able to pick out faces in the crowd. 

Crows might also benefit from recognizing individuals of other species. For an opportunistic scavenger, there’s an advantage to knowing which predator will tolerate their presence at the kill, and which will swat them out of the way.