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

by Bernd Heinrich

  “I’d like to make up with you, Merlin….” Merlin tentatively put one foot on Duane’s outstretched hand. More pillow talk. He hopped onto the arm, then off, but in a minute or so he hopped back onto Duane’s shoulder. The marital rough spot had been smoothed over, and the rest of the fishing trip went smoothly, as Merlin followed us, then rested quietly in the shade while we fished for bass in the pond.

  Merlin has emotions. He also remembers faces and events that he associates with them. He has moods. I do not know if he is a thinking being, but there is no doubt he is a feeling one.

  Aside from the crow call, Merlin has another unusual call I’ve never heard before—a distinctive two-note whistle that Duane invented and Merlin copied. Now Merlin appears to use it to alert his “mate” when something strange is nearby. He also uses it to draw attention to himself when he is flying high above Duane. Ravens in the wild also have individually distinctive calls. Perhaps that is one way of recognizing individuals. Certainly, Duane has no problems identifying Merlin when he flies high above him, as long as he calls.

  Merlin’s communication can also convey more specific information. One day, Duane was sitting down on a hillside and Merlin was exploring nearby. Merlin returned to him, perched on his shoulder, and began to peck him lightly and pull his collar. Then he jumped off Duane’s shoulder and flew a loop down the valley. He came right back to repeat the same maneuver. Duane said, “I knew unmistakably that he was trying to get my attention, so I went where he directed, and there I found a bobcat on a ground squirrel.” Hearing this anecdote, I wondered if raven mates might cooperate, or if ravens form symbiotic relationships with hunters?

  Merlin became animated again as soon as we started our homeward journey from the fishpond. We all separated, but now that he was going where he wanted to go, Merlin at first followed Duane exclusively, then flew the rest of the way home alone.

  Temperatures were near 101 degrees in the shade back at Camp Pozo. Duane offered Merlin a large stainless steel bowl full of water. Merlin jumped in and splashed with his wings working like an eggbeater. He emptied the bowl of water three times. He shook and preened on Duane’s knee after each bathing bout, then retired onto the trailer roof to finish off his final drying and preening before joining us inside the trailer.

  The TV was on, and everyone was slaking their thirst. Merlin was mellow and well-behaved. He spent the whole two hours patiently and contentedly perched on Duane’s knees or shoulder, except to politely take the corn chips we handed to him. Duane rolled one corn chip up in a towel. Merlin deftly unrolled the towel by pushing the roll forward with his bill until he reached the enclosed chip. He knew the chip was inside. He paid no attention to Lady and Katche sprawled out on the sofa. He knows them well, and vice versa. They mutually ignored each other even when less than a foot apart, but Merlin teases or attacks strange cats and dogs. He once showed a fright reaction on seeing a picture of a wild cat baring its teeth.

  By 4:30 P.M., when temperatures outside again became tolerable, Duane and Charles pulled folding chairs under the oaks and began limbering up their guitars to launch into an impromptu rock concert. Merlin perched as if transfixed on Duane’s knee the whole time. Although it was not hot anymore, his bill was open. His shiny blue-black feathers were smooth, and he held his head still. He sometimes blinked rapidly with the white nictitating eye membranes, showing his strong emotion. Amazingly, for another two hours he changed position only once, to hop onto the amplifier that served also as a table for beer cans. I don’t know if he appreciates music, but he certainly didn’t fidget one tiny bit during the two-hour concert. He was alert and scanning all around throughout. When the medley stopped, Merlin immediately stretched one leg and a wing on one side, then did the same on the other, and shook and preened as if he understood that the performance was over. Becoming lively again, he hopped off the amplifier and started pecking the edges of a guitar case.

  Duane thinks that certain sound patterns or frequencies “set him off.” For example, Merlin reacts to Andean flute music much as he does to the sound of a vacuum cleaner—with interest. Some might question whether the sound of a vacuum cleaner qualifies as music. Personally, I think music is in the ear of the beholder. My wife, who likes classical music, thinks Merlin’s tastes are like mine, which run to Bruce Springsteen and the Animals.

  During target shooting with a .22 rifle, Merlin reacts to shots with fright, although a truck motor running full blast doesn’t faze him. He reacts to the slightest rustle if he has not yet identified it. In the Santa Cruz apartment, he once came on full alert, craning his neck while Duane and Sue at first didn’t hear anything. Then they just barely detected delicate footsteps. A deer walked past the window. On seeing it, Merlin instantly calmed down and again became his old tranquil self. Seeing the deer did not alarm him as much as hearing the very faint but unfamiliar footsteps.

  What he sees as dangerous is difficult to fathom. He became excited when he spotted an eagle, even before he was attacked by one. He acted terrified of a real snake, yet treated an almost perfect imitation of one with nonchalance. He was upset for weeks, Duane said, by a frame of two-by-fours that served as a retainer for the stereo set, and he “went bonkers” when Duane put some fresh sage sprigs into his sanctuary. Merlin, like Jakob, was afraid of a tiny toy dinosaur put into his cage, but later he accepted it after he examined it on the floor of the house. He was afraid of a new broom. In general, he is afraid of slight changes in his environment, but he is much more afraid of some things than others. Duane concludes, “I have no clue why some things that you’d think might scare him don’t, while other seemingly totally benign things freak him out.”

  About a half hour before dusk at Camp Pozo, Merlin took off, banked steeply over the trailer, flew over the oak trees, and eventually reached cruising speed at about five hundred feet above us. The sky was clear except for some thin cumulus clouds, and we stood mesmerized, admiring his aeronautic skills as he glided over the hills and then circled back again and again over Camp Pozo. I did not have the presence of mind to look at my watch, but I videotaped for nine minutes. The whole flight must have been considerably longer. When he finally dove back down and on outstretched wings landed gracefully on Duane’s shoulder, it was 7:40 P.M. The sun was sinking, and the dry grass shone golden on the eastern hillsides. Duane walked his friend to the trailer, and Merlin hopped off and entered his sanctuary. It had been a most unusual day.

  Jakob and Merlin had revealed tantalizing glimpses of ravens that contrasted with my “scientific” field studies requiring large numbers of birds that yield data, which I analyze with statistics. Observing the two birds who had bonded with humans, with an intimacy they normally reserve only for other ravens, gave me a different perspective. Perhaps one could not hope to appreciate the mind of the raven, any more than one could claim to know the sociobiology of a remote tribe, without first living with if not marrying into it, as Klaus and Duane had done.

  Goliath and Whitefeather.

  FOUR

  Ringing Necks for Baby Food

  GOLIATH AND THE OTHER THREE ravens that I reared from nestlings were one of several groups that I have raised. At times, I had groups of more than twenty ravens caught from the wild as adults and held in my aviary temporarily. Each raven eats a lot of food per day, and as you know by now, feeding them has been a tremendous practical concern. What ravens eat is also of great importance in understanding their behavior, because food is a focus of the bird’s lives and has been a major principle in their evolution.

  I fed Goliath and all the other young ravens I raised to adulthood on a varied diet consisting mostly of meat, dog chow, boiled eggs, frogs, raw fish, and occasionally insects. They always begged loudly, yet often refused food if they had been fed the same things several days in a row. When only a month or two out of the nest, they yelled loudly and irritatingly whenever they saw me, then pursued me relentlessly. The amount of weight gained for the amount of protein fed seemed to be low. Did
they get a better diet in the wild? If so, what was that diet? In early May 1995, I decided to try to find out by going directly to a nest.

  A pair of loons had returned to Hills Pond on April 22, two days after the ice sheet broke up. The snow in the forest had finally melted, and spring was on its way. The robin, woodcock, phoebe, mourning dove, flicker, red-winged blackbird, cowbird, solitary vireo, sapsucker, white-throated and song sparrows, bluebird, and even tree swallows and kestrels had been back for two weeks. The first wave of wood warblers, Nashville and yellow-rumped, had arrived the previous week. As he does every spring at this time, a woodcock was making his spectacular display in the clearing by my cabin every evening, and the females would soon be sitting on cream and lilac-spotted eggs. None of the songbirds, the Passeriformes, had yet started to build their nests. In stark contrast, the largest songbirds of them all, common ravens, already had nearly full-sized feathered-out young.

  Birds are driven by their breeding schedule, which is fine-tuned to their food supply. Woodcocks come when the first soft earth promises earthworms. Kestrels must wait for snow-cleared fields to hunt for mice. The raven is much larger than either, and needs considerably more food. Each member of its rapidly growing brood of young needs huge amounts of protein daily. A raven, if lucky, can catch a mouse or two. It also can find a few stray worms, but it is not equipped to probe for them and routinely get them out of the mud as the woodcock does. Insects are far too small and rare to satisfy the demands of their large bodies. In any case, most of the insects are still in hibernation and unavailable when the young are growing in April. For the local ravens, the growth spurt of the young occurs in the four weeks at the end of April and the beginning of May. In the hundreds of nestings I have seen in New England, there has been only one exception to the relatively precise window of time when the ravens nest (Chapter 29). If something happens and the time slot is missed, or the first nest is destroyed, the birds wait until the next year to breed again. By contrast, in many other regions where ravens are found, they are much more flexible. There are even reports of them nesting in the fall, and it is difficult to characterize these nests as “late” or “early” (see Notes and References).

  Ravens usually have four to five young, all of which reach their full adult weight of three to four pounds in about three or four weeks. What food of such vast bulk, I wondered, could the adults possibly find for their young at the time of year to which their breeding cycle is synchronized?

  Ravens, like us, are considered omnivores. Given a choice of foods, my captive adults will eat the cholesterol-rich and fatty kind: cheese, grasshoppers, salty peanuts, eggs, butter, potato chips, and hamburgers. Next on the list come mice, birds, deer and moose meat, blueberries, maggots, tomatoes, carrion beetles, fish, oatmeal, and corn. Only a limited selection of this fare is available in the Maine woods in May.

  Along the coast of Maine, a most important food for the island-nesting ravens during chick-feeding time is seabirds and their eggs. John Drury, an ornithologist from the island of Vinalhaven, Maine, told me that the ravens there can frequently be seen flying over and landing in raspberry patches where the eider ducks nest. The eider nests in those raspberry patches are soon without eggs, and the nests’ down is strewn around. Near one cliff nest of ravens on Seal Island, John found the shells of thirteen eider eggs, and the picked-over skeletons of thirteen black guillemots. The year before, there had been nine eider egg shells and remains of two guillemots at the same raven nest. At a raven nest site on Great Spoon Island, John found shells of eggs of six to seven herring gull, one or two black-backed gull, thirteen eider, two cormorant, plus heads of three gulls, four eiders, and parts of two unidentified bird vertebral columns. Two weeks later, he found eleven more eider egg shells, and the remains of two guillemots and one blackbird. By a raven nest in a spruce tree on Metinic Island, there was evidence of similar fare. In contrast, near Bowdoinham, also on the Maine coast, Tinker Vitelli has since 1988 observed a pair of ravens nesting in a pine grove, and there the young are fed mostly freshwater mussels from a nearby stream. The ravens bring the mussels in whole and carry the empty shells away, never leaving any under the nest tree.

  Inland, the Maine forest ravens face a different situation. I suspected these ravens’ survival and reproduction were linked to deer and moose. In the fall, ravens invariably show up where hunters leave the entrails of deer or moose. In the winter and early spring, ravens may rely on deer that are killed by the sometimes lethal and tightly interrelated combination of cold, deep snow, starvation, and coyotes. Perhaps the cold storage of winter allows food to accumulate so that ravens can nest before the meat decays in the spring.

  Maine has an area of 33, 265 square miles, and an annual prehunting season population of about 300,000 deer. In recent years, the annual reported deer kill during the hunting season is approximately 27,000 animals, and the moose kill is about 1,500. The Maine Department of Inland Fisheries and Wildlife estimates that as many animals are killed illegally as are killed legally. Added to the count are the carcasses of beavers, coyotes, and other animals that trappers leave in the woods. This leads to a conservative estimate of about two meat piles per square mile over the year, in addition to the carcasses left from natural die-off.

  In the winter of 1992-93, I had picked up fifty-nine raven pellets under roost trees where a vagrant crowd was sleeping nightly while feeding on the calves I had provided. Ten of these consisted mostly of deer hair, and five of mountain ash seeds (see Table 4.1). These findings only suggest what ravens feed on. They are not a reflection of how much. Eating only one berry would produce seeds in a pellet, but a raven might feed on the viscera of a deer for days and pick up only a few hairs.

  Deer carcasses apparently are available, although the plucking of fur off live animals cannot be precluded. Of the more than fifty nests I have examined, all have been lined with deer fur. The nest linings also sometimes contain snowshoe hare fur, shredded ash bark, and on rare occasions, moose and bear fur. Once I even found moose, bear, hare, and deer hair all in the same nest; but deer hair is present without fail.

  If a pair of ravens with young had a whole deer carcass at their disposal, they would have not only insulative nest lining, but also a steady food supply for a several weeks, cold weather permitting. Weather not permitting, they would have fresh maggots rather than fresh meat by spring. My tame birds eat fresh maggots in preference to rotting meat. Having a deer or moose carcass available may often be a matter of luck. Even if the resident pair finds a deer carcass, there is also the problem of keeping it. If a crowd of juveniles takes over the carcass, the food supply will be gone in a few days. In my Maine study area, every one of the hundreds of large animal carcasses I provided was sooner or later taken over by raven crowds.

  Although it was only the first week in May, the breeding success of the local ravens had already just about been decided. Unlike other local birds that sometimes raise several clutches per year, or that immediately raise a second clutch when their first is destroyed, I’ve never seen any of the local ravens renest when their first breeding attempt was aborted. This year, two of the nine local raven pairs had made no breeding attempt. Three had started to build their nests, then stopped; and two nesting attempts failed after the nests had been completed (at least one of them had held eggs). Only two of the nine pairs had carried forward with the raising of a brood. Curiously, these two nests contained not the minimum number of young, which is two or three. Instead, they each contained five, which is near the maximum clutch size, although one year I found a nest that successfully produced seven young. The previous year’s nesting results had been similar to this year’s, with two successful nests that had brought off eight young together, most of whom were later killed by predators (Chapter 6).

  The first nest this year, at Braun’s Road, was abandoned shortly after construction. The second, the Weld pair’s, is consistently successful each year. The other pair that was so far doing well was the pair in the pines b
y the Robertson cemetery, which had failed last year very late in the breeding cycle. The very uneven distribution of young among these nine pairs was consistent with either an unreliable local food supply or divergent foraging skills of the pairs. I suspected the latter was the less likely explanation, because the cemetery pair that last year abandoned their nest with starving young had large, healthy young this year, judging from the ample mutes below the nest. Whatever catastrophe had befallen seven of the nine local pairs had not hit this pair. I wondered what food they were succeeding with.

  I had just learned of a method to determine what the young were fed without harming them in the least. All it required was for me to get to the nest with some pipe cleaners. The method was pure genius. It made it possible to get easy and unambiguous results to an otherwise difficult problem, with data that would be direct and pertinent. I thought, this is as good as it gets. I bought pipe cleaners and went directly to the nest tree.

  A pipe cleaner is a useful tool. It is a short pliable length of wire with some soft fuzz firmly attached to it. When this cushioned wire is bent around the neck of a young bird, the bird can’t swallow large chunks of food, but it does not stop begging and taking in food. The food simply collects in the gullet, stored there until one squeezes it up and out like toothpaste out of a tube.