The eagles came singly, diving with still and partially folded wings. They extended their wings just after passing the roost, then wheeled around to brake their descent, and came in for a gentle landing on a tree. As each bird landed, it made high chittering or peeping calls like those of gulls or sandpipers, which some think are contact calls for their mates. Scores of magpie nests dotted the willow thickets in washes between the sagebrush-covered hills. In this area, barely a five-minute drive from the motel, I saw many blood-smeared drag marks in the snow where hunters had pulled elk to the road. There would be many gut piles here, but no wolves. Would there be feeding ravens?
In the park, just a one-minute raven’s flight to the south, the wolves of each pack kill an elk on average every 1.5 days. Ravens always arrive immediately and start feeding at each fresh carcass. Ravens often arrive even before the elk is down. That evening, in town, wildlife filmmaker Bob Landis showed us film footage of a pack of wolves trotting leisurely among a group of elk, testing them for several minutes. One of them suddenly shifted gears and picked out one elk to pursue relentlessly even as it rejoined the herd. Eventually, the wolf grabbed the elk by the throat, and another wolf helped pull it down. Ravens were flying over the wolves as they made the kill.
Were the ravens completely tied to the wolves or would they feed at the gut piles outside the park? To find out, I drove up the little dirt road toward Jardine early the next morning. As soon as the dawn came, I heard and saw ravens. Most of them were in pairs, flying side by side from one end of the horizon to the other. Where might they be traveling, and why?
I started to walk up into the rocky, sagebrush-covered hills on a well-worn bison trail. Then I soon found and followed the red lines through the snow where gutted elk carcasses had been dragged. In three and a half hours, I located a total of sixteen elk gut piles, most containing liver, spleen, lungs, intestines, stomach, and diaphragm. There were no ravens feeding on any of them, though some had been fed from. Why hadn’t the birds descended on this food bonanza in large numbers and quickly obliterated it all? I was surprised, but what I saw was congruent with a set of experiments I had done in Nova Scotia.
I had gone in mid-winter to the Canadian Wolf Research Center in Shubernacadie, Nova Scotia, to observe ten semitame wolves in a ten-acre outdoor wooded enclosure. In experiments for testing raven’s preferences, I had put down two meat piles simultaneously. The wolves had fed as a group, and only at one pile at a time. There, as here at Yellowstone, the ravens had a choice—to feed with the wolves, or to feed without them. They invariably had chosen to be with the wolves. They had fed where the wolves were currently feeding or had just recently fed. These observations, given the raven’s fears that I had observed previously, were about as nonintuitive and surprising as anything I had ever seen or heard about ravens. It didn’t make sense.
Then I thought of my Maine ravens, who were so shy near carcasses that I had thought they might be almost paralytically afraid of dangerous ground predators. Did I have it backward? Had they been afraid because there were no wolves at the Maine carcass? I became excited, wanting ever more data. Maybe ravens are “wolf-birds!” Maybe they had evolved with wolves in a mutualism that is millions of years old, so that they have innate behaviors that link them to wolves, making them uncomfortable without their presence.
During my present attempt to increase my sample size of gut piles, I kept going higher and higher. I eventually reached deeper snow, and open sage country, then stands of Douglas fir where I heard red squirrels, red-breasted nuthatches, and Clark’s nutcrackers, in addition to ravens. In the Douglas firs, I came across blood flecks on the snow without carcass drag marks, indicating a wounded animal. I followed the spoor and soon found a dead elk cow with rifle bullet hole through her paunch. One or two ravens had left tracks on the dusting of fresh snow, and the birds had taken an exposed eye and a piece of the elk’s tongue. Given that no wolf or coyote had been near this carcass, that is all they could have taken.
The carcass had not yet been opened. I lanced it with my jackknife and skinned it on one side to let the birds get at the hundreds of pounds of red, unspoiled meat. While I was working on the elk, three ravens came near and called loudly. One landed in a Douglas fir nearby, looked, then made both short and long rasping caws, and flew off. I went back to the motel, imagining seeing a huge crowd of ravens when I’d return in a few days.
In the meantime, I had seen thirty ravens at an elk fawn within one hour after it was killed by wolves inside the park. Additionally, Doug Smith, leader of the Yellowstone wolf recovery project, had taken us to see the wolf pen at the Lamar ranger station, and there we found a large congregation of ravens, even though there was not a scrap of meat left inside the pen. When I hiked up to the elk cow carcass the second and then the third and last times, I was surprised that there was still no crowd of ravens, despite the plentifully available meat.
Shortly after breakfast one morning, we drove east toward Cooke City. Near Soda Butte we came to two parked vans, one with a radio antenna on top, which indicated researchers and was a good sign of wolves nearby. We stopped and made introductions. Nathan Varley, Lisa Belmonte, and Dan McNulty were training three spotting scopes on the hillside, and they invited us to take a peek through their spotting scope.
I saw all five Druid pack members lounging in the snow like one big happy family on siesta. Two of the wolves were jet black, two were gray, and one was tan. That morning at about 9:30 A.M., the pack had killed an elk cow. This was wilderness at last.
The elk lay well exposed under an aspen tree. The wolves had eaten little meat so far, and the second act in this drama was beginning. Three or four ravens and at least as many magpies were already feeding on the carcass. The ravens made no attempt to chase the magpies. A golden eagle swooped down and landed on top of the carcass. The ravens and magpies flew up briefly, then walked round and round the carcass, moving closer, and gradually resumed their feeding. The golden eagle left in a half hour, and a bald eagle took its place. Ravens and magpies remained. Not once did the ravens chase another bird to steal food from it, as they had done in Oregon. Not once did the ravens hesitate to go in and feed, as they do in Maine. With wolves present, the ravens had no fear of the carcass. They could go in and get their own meat.
A few hours later, it was snowing hard. The wolves started to get up from their nap and stretch. One returned to the carcass and fed briefly, then they all walked off together in single file, fading like ghosts into the thickly falling snow as they rounded the crest of a low ridge. The next day, I walked up to examine this carcass, finding many fresh coyote and weasel tracks. Even if the wolves ate little of their kills, all of the carcasses would eventually be eaten. The carcass would feed weasels, grizzlies, coyotes, foxes, carrion beetles and corvids, eagles, maggots, and possibly a wolverine. The wolves provided for all, but I expected that here, precious little would be left for the maggots next spring.
I was told that the ravens sometimes followed the wolves, and that if they were not seen visibly following the pack, then they were “always” there “within minutes.” Observers and students of wolves take ravens for granted, commonly remarking that ravens and wolves go together. So much is taken for granted that further comment, or data, have seemed superfluous. I tried to convince the wolf researchers otherwise, pointing out that nobody really knows the extent to which ravens may monitor or follow carnivores, or if they are simply opportunistic and sharp-eyed enough to see meat as it becomes available and then simply take it, as everyone assumes, but as my data disputed. My prod had an effect.
By the next winter, Doug Smith was in full support of appending a complimentary raven project onto the wolf project. Furthermore, Dan Stahler, who had already been following wolves and would continue to do so, agreed to take on the project by simultaneously gathering raven data. He would follow a protocol for getting systematic observations suitable for the first critical study on the raven-wolf association.
Dan repor
ted to me after his first seven days of watching the fifteen wolves of the Rose Pack in late November 1997. He had then observed twenty-four activity bouts of wolves that involved traveling, resting, chasing, at kill, and near kill. In all but three of these, there were ravens with the wolves. In contrast, of nine activity bouts of coyotes, ravens were present at only two. By March, Dan had data on two dozen very recent kills, and ravens were feeding at all “in seconds or minutes.” Raven numbers at wolf kills averaged thirty-two, ranging typically from fifteen to thirty, and were over eighty at one kill. The ravens routinely fed within feet of wolves, coyotes, and eagles.
Dan’s description crackled with excitement: “Last Wednesday, I watched a large grizzly bear lay on top of a fresh wolf-killed elk for over four hours while nine wolves and about twelve to sixteen ravens tried to get in to feed. A couple times during the four hours the bear slept ‘spread eagle’ on the carcass, while the wolves bedded less than thirty meters away. The grizzly was fairly successful in keeping all away, but was extremely agitated by the ravens that kept grabbing food despite his lunging at them. This topped my list of best field observations. Doug [Smith] has started recording data from his flights {in light aircraft} whenever he observes wolves. The other day he saw three different packs involved in elk chases (two ending in kills). During two of the chases ravens were flying directly above the chase or perched nearby. During one chase involving eight wolves there were eight ravens and two bald eagles soaring directly above. Amazing!”
Yes, I’ll second that. It is beginning to look as if ravens are dependent on wolves not only to kill for them and to open carcasses, but also to overcome their innate shyness of large food, whether in the form of a carcass or a pile (see Chapter 18). These facts hint at a relationship with an ancient evolutionary history.
Note: As this book was going to press, with the full cooperation and permission of park authorities, Dan had laid cut-open deer carcasses in established wolf territories where ravens, in over thirty previously observed cases, had always both shown up at wolf kills and fed with the wolves within minutes. In the twenty-five trials with the meat he provided that was unattended by wolves, no raven fed within the hour of observation period that his protocol called for. In the nine instances where one or two ravens discovered the unattended deer carcass, they circled the meat briefly and then left.
Ravens and wolves almost ignore each other when they feed together.
TWENTY
From Wolf-Birds to Human-Birds
DURWARD ALLEN, A PIONEER OF wolf studies, remarked that the ravens of Isle Royale in Lake Superior accompany wolves in their travels, feed at their kills, and sometimes even eat their scats. L. David Mech from the University of Minnesota, who has studied wolves for decades, has seen ravens chase wolves, flying just above their heads, and reported in his book The Wolf that “once, a raven waddled to a resting wolf, pecked at its tail, and jumped aside as the wolf snapped at it. When the wolf retaliated by stalking the raven, the bird allowed it within a foot before arising. Then it landed a few feet beyond the wolf, and repeated the prank.”
Mech noted, as Allen did, that ravens appear to follow wolves, and he speculated that both must possess the psychological mechanisms necessary for forming social attachments, and that individuals of each species include members of the other in their social group, forming bonds with them.
Rolf O. Peterson, a former student of Mech’s now at Michigan Technical University, also studied wolves on Isle Royale. He agreed: “There is more than playfulness between wolves and ravens. Ravens make their living by scavenging wolf-killed moose (the fresher the better) and as we start the day, flying along wolf tracks, we often overtake a raven doing the same thing. When wolves pause, the birds also stop, roosting in trees or swooping to the ice where they can watch and harass the wolves at close range. Once disturbed, wolves resume travel, which is what the ravens intended. Also, few wolf scats left on open ice escape the selective recycling provided by foraging ravens.”
It is not surprising, as another former Mech student, Fred Harrington from the University of Nova Scotia, has shown, that ravens can be attracted to wolf howls. They also come to gunshots where there is much hunting of large animals. The wolves’ howls before they go on the hunt are a signal that the birds learn to heed. Conversely, wolves may respond to certain raven vocalizations or behavior that indicate prey.
Dan Stahler, in his observations of wolves and their association with ravens in Yellowstone National Park, saw ravens not only following wolves on their hunts, but also hanging around at the wolves’ dens. Whenever the wolves at a den got ready to hunt, they howled, and the ravens loitering there started to get lively and to vocalize as well. The pups start to come out of the den at about three weeks of age. They are smaller than ravens and could potentially be killed by them. Yet the ravens, who occasionally walk behind a young pup, only gently yank its tail.
There are innumerable anecdotes of dogs interacting with ravens as well. As one example I cite Graham W. Rowley (in Cold Comfort: My Love Affair with the Arctic, McGill Univ. Press, Montreal 1996). “One day I watched a raven flying low over the Inuit camp, heading into the wind. Chasing after it were about twenty dogs. The raven decided to rest and alighted on a large rock, ignoring the dogs dashing toward it. When the leading dog was only about three yards away, the raven turned its head toward them and gave a single baleful squawk. All the dogs stopped dead, turned around, and trotted back to camp like sheep. The raven rested a few more minutes before taking off again into the wind.” Like the raven’s fear of carcasses the mutual attraction between wolf and/or dogs is a reflection of ancient selective pressures.
The raven-wolf association may be close to a symbiosis that benefits the wolves and ravens alike. Wildlife photographer and writer Jim Brandenburg, in his book Brother Wolf (see Notes), described ravens coming to an unopened bear carcass. They could get nothing but the eyeballs since ravens can’t open a carcass. The ravens then started yelling, and soon a wolf arrived and tore the carcass open. Brandenberg repeatedly saw wolves as well as coyotes come to a carcass that he provided shortly after it was discovered by ravens who were yelling.
Ravens may do even more than locate meat for the carnivores. Brandenberg says, “I can state unequivocally that, at a kill site, ravens are more suspicious and alert than wolves. In many instances, I have seen ravens become nervous at one of my small movements where the wolves seemed unaware. I believe that the birds serve the wolves as extra eyes and ears.” Wildlife filmmaker Jeff Turner suspects the same: “I can sneak up on a wolf,” he told me, “but never on a raven. They are unbelievably alert.”
In the High Arctic, ravens follow polar bears and feed at their kills, and in Yellowstone Park they also feed not only near coyotes and wolves but also sometimes with brown bear. Doug Peacock in Grizzly Years described watching a large grizzly sow and her cub at the edge of Wild Goose Valley in Yellowstone in late May. The grizzly dug and tugged at the ground among sagebrush, with ravens all around. At times, she reared and swatted at the cloud of ravens, flailing away at the air with her paws. The ravens probably also wanted what the bear was searching for, most likely pocket gophers or their seed caches.
Seldom do those whose activity provides food to ravens try, like the above-mentioned grizzly, to chase them off, especially wolves and humans. The Vikings, who usually got the upper hand in battle, eagerly welcomed ravens. To them the birds were an omen of victory, not doom. Why else would they fly their raven banner as they went into battle? If the ravens followed people anticipating a glut of carrion, it was for the same reason they now follow wolves. As we shall see, the raven still follows people and is said to follow deer hunters in the Scottish Highlands, where its presence is similarly regarded as a portent of a successful hunt (Ratcliffe, 1997).
From a raven’s perspective, the closest thing to the aftermath of a Viking battle occurs every October in northern Maine at the annual moose hunt. I needed to see it, and drove to Greenville at the tip
of Moosehead Lake to stay at Bob Lawrence’s hunting lodge near Rock-wood on the opening day of the hunt. The moose hunters streamed out at dawn, ranging up and down the dirt roads in their pickup trucks; nobody is keen to walk far into the woods to shoot a half-ton animal and then have to drag it out. I did not personally see a moose right after it was shot, but stopping to talk with hunters, I located six gut piles or their remains that were less than a day old. Ravens were feeding at all of them. One gut pile from a kill made the evening before had a stream of about fifty birds arriving when I checked it at dawn. One bird from this crowd pointedly came toward me, circled twice around my head at about ten yards, then flew back toward the others. This behavior made no sense to me. Did the bird mistake me for a hunter?
There are times when we perceive ravens to communicate with us. Craig Comstock, a raven-watcher from Starks, Maine, wrote of seeing a raven flying overhead. Craig called out, “Hey, how’s it going?” The raven immediately pulled a U-turn, did a half-roll, then went back on course. Craig waited until it had gone a bit farther and called again. Immediately, the raven pulled another U-turn, executed two back-flips and a half-roll before again returning to steady flapping. Craig commented, “I can’t prove the displays were for me. I understand the need for the scientific method, but…there are times when nature speaks just once, and it is a loss not to listen.”
Although ravens in New England are conspicuously shy, I have on several occasions seen one inexplicably come close to me, checking me out minutely. A Canadian Arctic biologist, Don Pattie, told me of tending small mammal traps on the Canadian High Arctic tundra when a lone raven flew near and landed. Don held out his hand and talked to the raven, which walked up and “took a bite into my hand and then flew off.” Don was perplexed, but he was not totally surprised. Ravens may do surprising things. A raven researcher from Austria said, “Ravens are incalculable—and uncanny magic emanates from them.” Another biologist, Steven Wainwright, told me of taking a walk in the woods near Vancouver, British Columbia, where he heard three ravens overhead. One of them came down through the trees and “talked” to him, so he began to talk back, making “raven-noises. I sat down on a log and decided to talk in normal tones. I said, ‘Hi raven,’ that sort of thing. The raven came near, and when I got up to leave, that bird followed me while the others flew away…It was a mind-blowing experience.”
Mind of the Raven: Investigations and Adventures With Wolf-Birds Page 27