Mind of the Raven: Investigations and Adventures With Wolf-Birds

by Bernd Heinrich

  I was in my blind only forty-five minutes when I heard heavy wing-beats. The raven had come back! It made only three or four alarm calls, then quieted down. Five minutes later, it flew down from near the nest in the pines (I could not see the nest itself) to the top of the snow near the bait. It did not go to the bait, though. The raven paced back and forth and all around for some ten yards to either side of the bait. Something, it knew, wasn’t quite right here—and it flew off.

  A half hour later, near 8:00 A.M., its mate came to the nest, making soft, high-pitched calls. Fifteen minutes later, one of the pair flew down to the snow, and walked up to the bait with little hesitation. My heart began to pound. Really hard. Weeks of frustration, hundreds of miles of driving, days spent on snowshoes walking laboriously through deep, heavy snow, endless planning, endless details—all were coming to fruition. Was this the moment? I had watched and baited them for weeks to learn their habits, to get them habituated to minor disturbances, so that they would not notice a hidden trap buried in the snow. And here was a raven, miraculously walking directly to a piece of meat with four traps set all around it.

  The bird stopped, looked cautiously all around, and advanced again. Then I saw it pecking—it was feeding at the meat! It fed, and fed some more, and more. Amazing! I had set the four traps, I thought, on hair triggers. It was at least fifty to sixty yards from my blind to the bait, and I had only a very narrow field of vision through all the many trees of the forest through the spruce boughs of my blind. Slowly, ever so slowly, deep within my spruce blind I raised my binoculars—rrack rrack rrack—instantly, the bird erupted in alarm calls and flew off. It had likely seen only a glint of light off the binocular lenses. It could not have seen me.

  About fifteen minutes later, a raven was back, again feeding at the same spot. After about five minutes, the raven flew up to the nest, possibly to feed its mate. It again made the high-pitched, soft mewing calls. Ten minutes later, one bird left the nest, making soft gro calls as it flew off. They always announce both their comings and goings with at least some kind of call. The female, who stayed at the nest, did her knocking call once.

  By 9:15, a raven was again back at the bait. It fed leisurely for several minutes, then flew off. I was dumbfounded, and I was shivering from the cold and the excitement. It was the third time the bird had come this morning. The raven had to get caught on the third time, I thought. Wrong.

  Some minutes after the raven left, presumably satiated, I heard very excited, sharp, high, quick caws. Two crows came flying over. The crows saw meat, turned around, flew back, and immediately landed, making the same excited caws. Would the ravens now chase them off? I waited—in less than two minutes one of the crows already started to feed. It was caught within seconds. The just-trapped crow was by no means silent, but its mate, hopping frantically in the branches twenty to forty feet away, was the more hysterical-sounding individual. I waited a minute or two to see if there might be a response from the ravens. I could see or hear none, so I came out of my blind and released the crow unharmed.

  As I left, snowshoeing back out of the woods, the two crows circled over me and continued to caw excitedly. I did not expect the ravens to be back for a while. For once, I was correct. No more tracks were seen near the bait here again, even though the pair nested in the pine tree just above it. I never did figure out how the raven avoided the trap. I never caught either of the pair, only two more crows.

  The next day, March 13, I trapped at a new spot where ravens had never seen me at a bait. It was a quarter mile from a nest and it was also a 1.5-mile snowshoe hike from the road, where I had seldom ventured. The trap was set at a carcass. This time, in only one hour I had caught a bird! It was silent, but as with the crows, its mate called loudly and angrily near me as I took the unharmed bird out of the trap.

  That same day this bird—the only resident we would catch—flew off with a radio attached to his tail feathers, beaming pulses at a radio frequency of 14,8130 hertz, or “8130” for short, our name for this bird from now on. Our study could now begin, although on a much more modest basis than we had planned. Most of the work had already been done.

  Number 8130 seemed calm throughout the whole handling procedure. Since his feathers had become soaked, he was clumsy in flight when we released him up near the cabin at dusk. He would have to dry off before flying back to the nest. At first, he stayed until after dark in the Alder Stream valley just below the cabin. Wondering if he would travel at night, I got up near midnight and made another radio check. He was gone, but there was a very faint signal from the nest direction. So he had flown in the night. After this, Ted, Delia, and Eileen tracked him every day from dawn till dark. In the first two weeks of tracking, he spent most of his time alternating between the nest site and a cow carcass that a coyote trapper had dropped in the woods.

  I returned to the nest on March 25 to determine if the female was, as I presumed, incubating. It seemed time for her to incubate, because I had seen the two birds approach the nest, with one carrying nest lining, on March 12, the day before I captured him. There were no birds near the nest this time, and none flew off the nest when I banged on the tree to try to flush off the incubating female. Was the female an exceptionally tight sitter? Was the nest abandoned due to my previous presence here, or due to stress associated with my tagging one of the birds? The nest was about ninety feet up in a giant, thick white pine tree that was nearly limbless up to sixty feet. I did not dare risk my neck climbing this very difficult tree to check the nest contents. To find out if the nest was still active, I would have to watch it.

  I made myself comfortable about fifty yards from the nest, hiding under a dense young fir tree next to another thick pine. My attention was fully engaged as I tried to detect a sound or a flash of black wings.

  Then a miracle happened. The radio signal got louder. 8130 was approaching. I heard the beautiful, clear, bell-like xylophone knocking of a female raven. Within seconds, I heard it again, closer. Then I heard it again and again. There was no doubt, both he and the female were approaching the nest from the northwest. Looking through the fir branches in the direction of the calls and radio signal, I saw black specks approaching. Not one, or two, but three!

  I could easily conjure up a rationale (however true or false it may be) to account for a third bird in a territory. Perhaps it was a male sneaking in to mate with the female. Perhaps it was a neighbor trying to damage or destroy the nest to enlarge its own territory. But whatever reason I could come up with, it invariably had to do with the third bird being up to no good, and the pair doing their best to evict him or her.

  One glance at these birds, however, told me that I was seeing something entirely different. The three birds flew calmly, wing-tip to wing-tip. As they came closer, I heard the soft gro calls that signified trust and friendship. These three birds were friends, and the idea that a territorial pair of ravens had friends outside the pair-bond that they tolerated, if not invited near the nest, seemed extraordinary.

  I watched spellbound as the three, now chatting softly among themselves, all flew into the nest tree. Two of the three birds landed directly by the nest, while the third flew near it, then veered off and calmly flew back in the same direction from which they had all come. The pair stayed at the nest for only a minute, chatting constantly in low tones. I heard the begging call that females make when wanting to be fed near the nest. When the two left the nest, they first perched in a nearby pine for another minute, and then flew off in the same direction the third bird had just flown.

  I wanted to build a blind right then and there and keep the nest under long-term observation, but other approaches were needed. My staying there would merely increase the chances of disturbing the birds and possibly disrupting their breeding effort. I would have to forgo further surveillance until much later, when disturbance would less likely disrupt the breeding.

  We left the nest alone, but we frequently found our bird at a trapper’s cow carcass about two miles from the nes
t. When we covered this carcass up with brush to see where else 8130 might forage, he usually disappeared from radio contact. Judging that incubation must surely be in progress, I visited the nest again on March 29. When I came close, 8130 was in the pines near his nest, and he made alarm calls and left. As before, no bird flew off the nest when I hit the nest tree with a heavy stick. Odd, I thought. Where is his mate?

  Again, I hunkered down in my hiding place under the fir tree next to the thick pine. Again, about half an hour later I heard the beautiful, clear, xylophone-like female calls from the northwest, and they were repeated, coming closer every few seconds. As before, three ravens came to the nest as a group, flying wing-tip to wing-tip. All three flew directly to the nest or within several feet of it. I again heard a female’s food-beg. Within several seconds, one bird left and flew back in the same direction that they had all come. Just as before. The pair remained at the nest for a minute, making soft conversational comfort sounds, then they perched in the pines by the nest. Unfortunately, this time they discovered me, and both made alarm calls and left. When I returned a week later, the nest had been abandoned.

  Number 8130 had become our focus. Our very reason for living at the cabin revolved around our day-to-day surveillance of this one bird. Our conversations revolved around him—a bird only I had actually seen, though he revealed himself to all of us via the radio transmitter attached to his tail. Later, throughout April and early May, whenever I saw him he was with only one other bird. Who had the third bird been? A dozen tagged birds might have given us a clue. We could only guess, and we inevitably came back to the apparent breakup of the nesting cycle just at the moment when the eggs were about to be laid.

  As we loitered in the evening around the cast iron stove while waiting for fresh bread for supper, our conversation and thoughts about the nest failure ran to the fanciful and jokingly anthropomorphic.

  “What do you suppose happened?” someone would ask, and we’d launch into imaginative discussions of various scenarios. For example:

  Here she is one night, we reasoned, as always expecting him to come to her side by the nest to feed her and sleep beside her. He doesn’t show up. She becomes hungry and anxious. Finally, long after midnight he comes back, weak and disheveled, with that strange extra tail feather and a weird shoulder patch. “You been where?” she’d ask. He would try to explain. And she’d say, “Yeah—sure!” So now he’s all weak and lazy the next morning, just when he is supposed to mate because it’s now time to lay the eggs. But he isn’t interested in sex just yet, nor does he feed her. She eventually sees another male, a neighbor. She displays to him. Feeling acknowledged, he follows her, hopeful. Maybe it is a male from a neighboring pair they both knew already. Maybe it’s an unattached male. In either case, it is a bird that her partner knows, too. So he tolerates him, if she does. The funny part is that this scenario could in principle actually be close to the truth.

  Some anecdotes mean more than others, because they are decisive and leave less room for interpretation. The three birds at one nest were not an interpretation. During February, I had at three different times seen groups or a group of five ravens flying together. Later in March, I had twice seen three flying together on the other side of the lake. I had always favored the most probable explanation, that these were groups of juvenile vagrants. Now I wasn’t so sure. More was going on here: Territorial ravens were not always reflexively aggressive to all others outside their pair. But when and why not? I needed to see details of bonding behavior, something that my tame birds might teach me.

  Raven friends.

  NINE

  Partnerships and Social Webs

  MY OBSERVATIONS OF THE THREE birds spurred my desire to understand more about bonding behavior. The best and perhaps only thing I could do for the time being was to engage in long-term observations of the birds I knew well, Goliath and his groupmates and subsequent aviary birds. I already knew my birds were highly attentive to, apparently curious about, and at times aggressive toward strange ravens coming near. Another juvenile raven in the vicinity caused them to watch, listen, and call, and the newcomer usually came down to the aviary. All sorts of social behavior transpired, the nature or purpose of which I didn’t understand. Perhaps the newcomers were interested in the food in the aviary, and the aviary birds were trying to defend their food; but I’m not convinced that this obvious explanation is the right one. The same behavior occurred when no food was visible. When I put food outside in the snow, the newcomers commonly ignored it, yet interacted with the birds through the wire. They postured at each other as though trying to show off and go through vocal repertoires.

  Wandering juveniles are a gregarious lot. By the dozens, and sometimes hundreds, they fly high in the sky riding the updrafts, barrel-roll back down, catch air, and spiral back up. They sky-dance in pairs and sometimes triples during these raven flight “parties.” I have tried to see if the two are stable pairs, or if third birds cut in to exchange partners, but the action is usually too fast and too far away for me to be able to tell. Similarly, apparent pairs come to baits in the morning from communal roosts of juveniles. Could juveniles form pairs? I was skeptical, even though field data had long suggested the possibility. But Goliath and his mates gave me fresh insight on pairing.

  Except for mouth color, ravens a month out of the nest look almost identical to adult ravens. Adults can begin to breed at the age of three years, but sometimes do not until seven. Males and females have unisex garb. We can distinguish them by certain displays and vocalizations, but neither shows up reliably until the birds are well into their second year. Yet in the aviary, distinct pairs form before one year, and paired birds show distinctive displays toward each other (Lorenz, 1940; Gwinner, 1964).

  On February 8, at nearly one year of age, Lefty bowed, fluffed, fanned her tail, and did her first very clumsy rendition of the female-specific knocking display to Fuzz. That is how I knew she was a female. Did he? I needed to wonder, because I previously had one pair of ravens, two very large dominant brothers, who bonded and built a perfect nest, then fought viciously when one tried to mate with the other at egg-laying time, i.e., just when the nest was finished. From this I deduced that the condition of the nest, rather than the condition of the female, is likely the cue for mating.

  The brother’s friendship survived despite numerous vicious fights at attempted matings, and despite availability of females. Lefty, in the next few days, repeated the display numerous times as if practicing or communicating to no one in particular, I never heard Houdi, the other, slightly smaller raven I suspected of being female, give this female-specific call until about a year later.

  As I write, in June 1998, I have another group of six juveniles that are a year out of the nest. Of these six, a male, Blue has been paired with a female, Red, since last January, when they were only seven months out of the nest. (The birds are named for the color of the ring that marks them.) They perch next to each other regularly, preen each other, and feed together. Blue is the most dominant bird of the group. He and Red eventually fed amicably side by side, but he attacks all birds except Red. For all appearances, they are a couple, yet if they were in the wild they would be wandering juveniles, and they would not breed for two or more years.

  We don’t know why young ravens socialize, but by doing so they enter a social web that could have relevance beyond information exchange about food. Socializing reduces aggression; to be familiar to the others at food is to be tolerated. In addition, in order to meet potential partners, the birds have to show themselves, getting exposure to others. Partnerships may lead to mating. In addition, being in a feeding aggregation could also be a large part of making social contacts, leading to alliances. If so, the birds must recognize individuals. It has often been assumed that some birds can do this, but we don’t know how. I hoped eventually to observe individual differences in my charges, to maybe get hints if and how they might do so themselves.

  When Goliath and my other three young ravens
were just weeks out of the nest, they followed me when I went for daily rambles in the woods. By the end of July that year, the four were showing signs of independence. I feared that, like other young ravens I had reared, they were nearly self-sufficient and would soon leave me. Since I wanted to study pairing (and more), I retained them in my aviary complex.

  By the first fall, some pairings already started to develop. Commonly, one bird perched close to another and bent its head down to solicit preening. Such solicitations indicated who wanted attention from whom, and whether or not they received preening indicated who was interested in providing satisfaction. At first, every bird preened and was preened by every other one. The preening partners gradually became more specific, until they eventually became nearly exclusive. For example, Goliath formed a preening partnership with Lefty, and Fuzz preened exclusively with Houdi, and vice versa. They were “going steady.” (I presume that it was only random chance that Goliath ended up with Lefty, his sibling.) Might these pairs also become nesting partners? To find out, I had to separate each pair into their own aviary.