Mind of the Raven: Investigations and Adventures With Wolf-Birds (39 page)

When he finally got to the last donut, he flew off with it into an adjoining aviary, where the others could not see where he would hide it. And as I expected, the others took that as the opportunity to steal the donuts he had cached nearby, while simultaneously guarding the pile. They also examined his false caches, proving that he had been in fact a credible liar, regardless of what he may have intended. He had not been cooperative in repeating his two-donut carrying trick. He had had a much different agenda than mine. He was calling the shots here.

For my third donut test, I closed Whitefeather into the adjoining aviary and left her four donuts. The three birds, Fuzz, Goliath, and
Houdi, flew and impatiently walked back and forth along the wire by the donuts they could see but not reach. In contrast, Whitefeather casually walked to the donuts, daintily picked at one, and walked off with it. It took her a full six minutes to cache just that one. She cached a second one with equal languor, then just left the other two donuts to lie tauntingly where they were—in front of the other birds, who frantically paced back and forth along the wire screen, until she finally did cache them, in no great haste.

About a month later, on November 10, 1995, I confined the four birds in half of the aviary, where they had little room to get away to cache in privacy, and I put four donuts on the ground. As always, Fuzz was at them immediately, keeping the other three away. He was not hurried, picking up crumbs and only caching a few of them nearby. He allowed his mate, Houdi, to come near, and she grabbed a half donut and left. A little later, Whitefeather rushed in and grabbed a whole one. Fuzz instantly mounted a vicious pursuit, and she dropped it. He picked up the purloined donut and returned it to the pile, putting it next to him. The grab-chase-drop-return sequence was repeated three times in ten minutes. He continued slowly to walk around the donuts as if guarding them, then broke one apart into two pieces and cached the pieces nearby, one at a time. He broke the next donut into five pieces, caching these pieces also one at a time, the small pieces first. With only a half donut and one whole donut remaining, he picked up both together by placing the half one onto the hole of the horizontal one balanced on his lower bill. Twelve minutes had elapsed. Fifteen minutes later, he was still carrying the one and a half donuts with him, while the other birds had meanwhile uncovered the caches he had made. Perhaps he knew that, given the confines of the aviary where he could not escape the others’ eyes, he couldn’t cache what he now held, either. That’s flexibility. Other examples are legion, but not all examples are equally valid.

When I give my ravens dry bread, they sometimes dunk pieces in their water dish. Such behavior is not hardwired. It is rare. It has been interpreted as a deliberate strategy to soften the dry food to make it
more palatable. To me, it looks more as if the behavior is simply incidental. Birds eating dry food get thirsty. While carrying the dry bread around, so that others won’t get it, they arrive at the water dish to drink. I’ve seen Whitefeather stop at the dish, hesitate, look all over for a safe place to put the bread down, and finally just drop it into the water where she can guard it easily while she drinks. Then she retrieves it out of the water after her drink. Ravens drop rocks, pieces of meat, sticks, and other toys into water as well. It is possible that a raven could, by such seemingly random behavior, have an “Aha!” experience and then quickly learn goal-directed bread dunking. However, they seem quite content to eat dry bread.

There are numerous reports of ravens dropping sticks, stones, and other objects. It is usually assumed that the birds are acting deliberately for some purpose. However, most reports of object-dropping behavior that I’m aware of are too incomplete for conclusions. Bob Sam told me of a raven in Sitka, Alaska, who took an unshelled walnut, flew up with it several times, and dropped it on the concrete. The shell didn’t break. Finally, after the raven dropped it on the street, he perched atop the Sitka Hotel. A car came along and ran over the nut. Then the bird flew down and ate the nut’s contents. Hilmar Hansen, a railway worker from Montana, told me of ravens placing deer leg bones onto rails he was inspecting, and coming back to feed on the marrow. These acts may or may not have been deliberate. More anecdotes, and especially more details to each anecdote are needed to come to conclusions as to what drives the raven’s behavior. Have there been a thousand unreported instances of ravens flying with nuts and eventually dropping them at random? Would a raven go to pick up the pieces of
any
bone or nut that was run over by a vehicle? Had the bird previously dropped a tough walnut in frustration at random, to be rewarded with food by a passing car? Did they learn by trial and error, and then know by insight what they had done? Intelligent behavior may result from a combination of curiosity, exploration, persistence, patience, keen observation, learning, and opportunism; but insight is difficult to prove because it is not necessarily a prerequisite for clever behavior.

Roger Smith of the Teton Science School wrote me: “I was banding young ravens on the east side of Teton Park in 1992. The nest was in a Douglas fir, about 35 feet up. While banding the third of five young, one of the adult ravens landed on a branch approximately 1.5 meters from me. This bird began vigorously tapping and rubbing its beak on the branch, vocalizing, and moving back and forth on the nest branch. I then noticed it had pulled a cone off the branch and began making low vocalizations with the cone in bill. By this time, I was banding the fifth nestling when, to my surprise I was hit in the face with a cone. I stopped and watched as the bird walked down the branch about two feet and pulled off another cone. At his point, I tried not to make eye contact with the bird but watched the behavior more closely. The bird walked back along the branch to the same distance from me, began the same beak tapping and vocalizations, then flicked the cone toward me, only this time the cone landed in the nest. The ‘throwing’ movement was incredibly quick. The bird flew off the branch only moments after this second encounter.”

It is not possible to say with certainty if that raven knew what it was doing, although it seems unlikely the bird had learned the act of throwing, that cones can be pulled off for throwing, or that throwing them at nest predators might deter them. Insight could account for all three.

Mental representation of successive images that are projected in the mind like a movie is consciousness and the modus operandi of intelligence. We use mental projection so routinely in almost all activity that we take it for granted. When we throw a ball, we see a trajectory to the intended target. We make choices to achieve very specific anticipated results. Without anticipating or projecting the results of the various alternatives to generating a sequence of actions, no intelligent strategy is possible. In effect, the fundamental capacity to develop strategy requires a capacity to visualize that which is out of sight, and that which has not yet happened but can happen. To ravens, that which is out of sight is, as with us, also not necessarily out of mind, as can be seen even in trivial examples.

One time, I had a white opaque plastic bag with a fresh DOR (dead on road) woodchuck. Goliath had seen me cut off a leg for him,
and then put the chuck back into the bag. I walked away down a woods path. I hadn’t gone far before he was behind me, begging. Odd, I thought. How could he be hungry after I had just given him a whole woodchuck leg? I left him another leg. Instead of eating from it, he hurriedly hid it as I was walking off, and then flew right behind me, again begging some more. “Okay, Goliath, you know there is more in that bag. You want the whole thing. So here it is.” He does not follow me if he sees me put a piece of food into a bag, and I then retrieve it and give him the whole thing. He keeps track of objects even after he no longer sees them. Is that capacity advantageous in the wild?

Kristi Dahl published an anecdote in 1996 in
Wyoming Wildlife
that suggested the immediate usefulness of keeping mental track of objects out of sight. From her porch in Grand Teton National Park, Kristi observed Uinta ground squirrels scurrying around in the muddy sage grassland when the shadow of a raven overhead made them dash for their burrows. “We watched carefully as the adult raven landed nearby and approached a squirrel burrow…. The bird began to peck at the dirt, scooping loose soil with its beak. Suddenly, the raven stopped digging and gave a series of high-pitched, throaty yells. It was immediately joined by a young raven, evidently its offspring. The young bird began to beg and call as the adult continued digging…. Finally, about eight inches below the surface, the raven found its lunch. Pulling up a full-grown ground squirrel from the hole, it stabbed the animal several times…. The squirrel was torn apart and fed to the young raven before the pair flew off.”

It is only a small step from seeing something in the mind when it is out of sight, such as prey or an enemy, to remembering past moves and anticipating future moves and reacting appropriately. There are many suggestive examples that are consistent with the idea that ravens are capable of all of the above, although most of the examples are not tightly enough constrained to allow unequivocal interpretations. Here are a few of them:

As reported in the Manchester (England)
Guardian
of June 25, 1995, a trapper in Prince Albert National Park in northwest Saskat
chewan observed a raven feeding on an animal killed by a wolf. The raven occasionally interrupted its meal to lie still on its back. Eventually, the trapper noticed that this happened every time ravens flew by overhead. He conjectured that the raven played dead so that to the birds overhead the scene would look like yet another raven had died from poisoned meat bait and would give the place a wide berth. Again, we need more details to draw such conclusions. Ravens roll on their backs in play. What, precisely, were the timings of the back-rolls versus the overhead flights?

Some of the varied uses of the bill
.

When the woodfrogs were chorusing near my aviary, I got four from a local pool. I put the first frog out of sight into a square, brown, foot-long PVC drainage tube. The birds had played with the tube before and presumably knew it was hollow, but they were shy at their first sight of a frog. They perched and watched from up in their loft, about thirty feet away. As I walked away from the tube, Houdi flew
down and first looked in one end, then ran around and checked the other end. The frog could not be reached from either end, but she picked one end of the tube up and the frog slid out. She grabbed it, flew back up onto her perch, ate the frog, then came down to walk on the aviary floor. When she walked past the tube, she did not peek in, apparently remembering that I had put just one frog in and she had taken that one frog out.

Several hours later, I put the second frog into the tube. Fuzz and Houdi were on full alert, intently peering down from their perches at the tube as I walked out of the way. Fuzz was the first one down this time. He bent his head down to ground level and peered into one end of the tube. He must have been able to see the frog, but he could not reach it. Was it therefore unavailable? No problem. Fuzz did not hesitate even a fraction of a second. He quickly walked around to the other end, reached in, and pulled the frog out. While he was eating it, I put
the third frog into the tube. Houdi peered at the tube from her perch for a half minute before she flew down and looked in. Since the frog apparently had not moved, she simply reached in and pulled it out. After eating it, she retrieved the tennis ball she had played with previously and stuffed it back into the tube.

While the ball was solidly stuck into one end of the tube, I put the last frog in the other end, presuming it would escape deep into the tube to lodge against the ball. Houdi left her perch and looked in. The frog could not be reached. It must have already moved down the tube to the ball. So she walked to the other end of the tube and tried to remove the ball. Fuzz joined her. He first peered into the open end of the tube, then walked to the other end and tried to remove the ball. It must have been stuck solidly, because it took him a full half minute to remove it. When he finally did, he grabbed the frog. Had he “filled in the blanks”—imagined where in the tube the frog lay? Do ravens have X-ray vision or can they can reconstruct spatial relationships in their mind? I speculated that the latter was more likely than the former.