One Wild Bird at a Time

by Bernd Heinrich

  These observations did not reveal the function of the group flights, only that jays could assemble and large groupings must have included more than one immediate family. It seemed the jays were not necessarily solitary at all, nor strictly restricted to a home territory. Yet even when their calling made the woods seem full of jays, they did not travel around in flocks within the woods. Are they nevertheless still a group, one that while traveling over the forest keeps in contact by sight, but when dispersed within the woods does so by voice?

  Unfortunately I was unable to identify individual blue jays, except one that I nicknamed “the wheezer” (because of its distinctive nasal twang), a resident that I heard fairly often from September 12, 2013, until the next fall, and then again the following year. It is likely, though, and intriguing to speculate about the possibility that if the jays are members of groups they can identify many individuals by their aural signatures.

  The rare and often dramatic instances of jays’ coming together—to mob a predator, in a rendezvous for mate selection, or for long-distance travel—are overshadowed by their far more common tendency to be spread through the woods as individuals. But it raises the question: What does a jay gain by being solitary when it is alone in the woods? The answer may be found by determining what it does. I decided to follow one and find out.

  November 18, 2011. It was a still and cold morning in the woods next to my cabin shortly after the sun came up. A blue jay near me perched high in a tall sugar maple tree, fluffed itself out, and swiveled its head to look here and there. I stood with my cup of hot coffee, greeting the sun and whatever else might come, expecting and soon seeing the pair of blue jays that had been daily for months to my birdfeeder.

  I went back inside the cabin to warm myself at the wood fire in the big iron stove. Nothing unexpected happened until, some minutes later, a blue jay screamed the long high-pitched calls, one after the other and for several minutes on end. It was calling from the woods, about a hundred meters distant. Its persistence was unusual, and I wondered if it was alarmed or surprised by something, as per the generally accepted interpretation of screaming.

  I peered into the woods to try to see some cause of the prolonged screaming. As usual the screaming bird was hopping around, seeming unconcerned, and randomly looking in various directions. But then I heard a faint scream from the east, perhaps a kilometer away. I couldn’t tell whether it was random or answering. Yet “my” nearby jay immediately stopped calling, and I again heard the call of the distant one. My jay called again, and the other replied, sounding nearer this time. Mine then stayed silent, but the other repeated its calls at intervals, and each time it called it was closer.

  A blue jay carrying an acorn.

  I had previously seen lone jays call from a treetop, fly off in silence, land in another treetop, call again, and repeat this pattern, thus moving in a specific direction. Now the distant jay was coming up the slope and mine flew to the eastern edge of the clearing, precisely where the other one soon arrived. They landed in the same (long since bare) red maple, but although seemingly ignoring each other made the soft whisper calls often made by couples. Then both came to my feeder, filled their throat pouches with seeds, and flew off separately, high over the forest. I realized then that a blue jay’s home area can be huge. The forest is dense, and it may normally make more sense for a pair, or birds of a group, to forage separately than together, as long as they rely on scattered small food items that must be searched out one by one. But if these two were a pair, what about an extended family, or a social group?

  November 6, 2013. It was a wind-still morning, and I was in the woods before 7 a.m. I soon heard the typical long jay calls, first to the north, then the south, east, and west. After several minutes of silence I heard another call, and then yet another from a half-kilometer or more distant. I sat on a rock and waited as a noisy pair of red-breasted nuthatches in a flock of chattering chickadees passed through the woods. Suddenly a blue jay arrived and landed about two hundred meters from me, high in a huge red spruce tree. I didn’t budge. It was silent, hopping through the thickly branched top of the tree as though searching for food, as it picked here and there. A few minutes later, and without interrupting its exploration of the tangle of branches, it made a few of the usual long, loud, two-note scream calls. Sometimes it abbreviated these calls to make a series of three, varied the pitch, or slowed down or speeded up the tempo. All the while it kept hopping, pecking here and there, and foraging, without ceasing its calling.

  At a distance of a kilometer or so I heard the faint call of another jay. The one I was watching paid no apparent attention to the sound, not interrupting its investigation of the twigs at its feet. In about twenty-five minutes it traveled only about three hundred meters. It made two or three different scream calls, one call with a higher pitch, and a series of lower, softer calls. I could see far into the leafless maple woods, and there was not another jay in sight. After a half-hour the solitary jay flew off silently to the northeast, from where I had heard no calling. On the face of it, it seemed to have talked to itself the whole time. But had it been heard and listened to by others?

  These snapshots of a blue jay in the woods might not have been interesting except for the contrast with what happened two hours later in the same woods. I heard a red-tailed hawk scream and saw it sail low through a silhouette of trees, quickly out of my sight. (I was glad to see it, to confirm that it really was a red-tailed hawk, because the local jays mimic the calls of both the red-tailed and the very different-sounding broad-winged hawks to apparent perfection.) Almost immediately a blue jay started calling, then two, then three chimed in. Within a minute there were more jays and I could no longer distinguish individuals. Then there was a melee of calls, and yet another jay flew over me out of the distance and in the direction of the commotion. These were indeed the jay screams, but they had a different tenor from the lone foraging bird’s previous calls that might have been heard but were usually not answered. Fifteen minutes later the jays became silent. Many jays must have been in the nearby woods before the hawk came, and likely afterward, and they would have heard the first jay, the one I watched, vocalizing as it foraged near me.

  From then into early April I heard the jays’ screams many times each day. Along a stretch of six miles (ten kilometers) of dirt roads I seemed to hear them everywhere. Groups of two or three flew here and there in no specific direction, and there was hardly a moment when I did not hear a jay calling from somewhere in the woods. But after April 7 the woods were again silent of jays. I saw none, as if the woods had been swept clear of them. Again only a pair remained by my cabin.

  The observations are consistent with the inference that although blue jays are solitary in some of their food gathering in the northeastern forests, it is perhaps because they often have to be. Yet they broadcast specific loud screams into the otherwise silent woods, and these neither attract others nor warn others, but serve instead as distant markers of each other’s or a social group’s presence. Nevertheless, blue jays can and do recruit, but through other calls that also draw attention to themselves.

  The scattered blue jays are sometimes in flocks, but they do not look like flocks while the birds are feeding separately on widely scattered food in a forest. On the other hand, movement to new foraging areas and clumped food such as the locally and seasonally available acorns and beechnuts require long-range movements, which are made by the group. Highly clumped nuts are available only in the fall, and the supply in a given location varies from year to year. In the fall of 2014, for example, unlike in 2013, there were no beechnuts at my study site in Maine, nor were there any acorns there. The acorn supply was spotty—in some areas along my route between Maine and Vermont the red oaks had few or none, and in others the trees were loaded with them. Food caching for future use is one way of dealing with a distribution of food that is uneven in space and time, but in the northern forests blue jays cannot rely on storing food for use in the winter, because the snow is
often too deep for them to recover their caches. Having to move seasonally as well as geographically, jays somehow manage to maintain social cohesion and an apparent flock organization without staying in a flock continuously. They keep in touch vocally when separated, and can then assemble and move together.

  I had now arrived at what I thought was the most reasonable hypothesis for these long, loud calls that were usually not recruitment signals, and had buttressed it with independent confirming evidence. Yet I wasn’t satisfied. What could be the advantage of such seemingly costly behavior of “talking to themselves” (which might attract the attention of predators)? The reason that had come to mind, namely keeping in touch, just did not seem sufficient as a selective pressure.

  “Animals,” as Mark Twain authoritatively stated relative to blue jays, “talk to each other . . . but I suppose there are very few people who can understand them.” The scream of the blue jay, I now suspect, has a basic message that simply says, “Here I am. How are you?” Hearers can then feel reassured that they are not alone in the area, and can either ignore it or reply, “Here I am, too.” Depending on inflection, length, repetition, pitch, and context, it has subsidiary meanings such as “All ok,” “I'm excited,” or “This is scary, come check it out.” Very different loud sounds uttered only at the spring rendezvous may mean “Look at me: I'm available.” Soft whispers in the presence of a mate may mean “I like you. I want to stay with you.”

  In any relationship where the individuals are separated (such as by distance or by a visual barrier like a thick forest), giving a shout now and then—whether or not there is an immediate answer, so long as it is heard by the intended recipient—could be important without conveying a specific message. After realizing the likely nonspecific but nevertheless meaningful social nature of the blue jay scream, I thought that now I might be less hesitant to call, e-mail, or send a letter or a hello, even when, as almost always, I had nothing important to say. I had learned more from the blue jays by inferring something from them than by attributing a message to them.

  10

  * * *

  Chickadees in Winter

  BLACK-CAPPED CHICKADEES, ALONG WITH BLUE JAYS, ARE iconic birds of the winter woods. They travel through the forest in small flocks of usually fewer than a dozen. I may hear their cheeps and occasional chick-a dee-dee-dees as they pass by while busily hopping among the branches from one tree to the next. The little fluff-balls in flocks grab attention by their cheerful energy and unflagging persistence in the coldest winters, and a day or two after the winter solstice the males start to sing their territorial or love songs.

  I started watching chickadees closely and taking notes on their winter flocks, in which they were often in company with my favorite birds, the golden-crowned kinglets and red-breasted nuthatches. The flocks varied hugely in size and composition, and I hoped my observations would reveal something interesting, maybe some insight about the advantage of being in flocks.

  If I had read Susan M. Smith’s 1991 book The Black-capped Chickadee: Behavioral Ecology and Natural History, which cites 610 scientific references, I might have realized that chickadees were many researchers’ favorite subjects. Perhaps there was nothing more for me to see—or everything. I chose to believe in the latter possibility, simply because chickadees are ever present where I live. They are one of the few birds able and willing to stay year-round in their home in the north, enduring howling winds, snowstorms, sub-zero temperatures, and the constant challenge of finding something to eat in the barren woods. Birds of other species follow them not only as flock members, but also as onlookers. On July 21, 2006, a chickadee alarm-called to me, and almost immediately eight others, plus a junco, a red-eyed vireo, and a redstart, gathered round me. These were not all members of a flock, but the advantages of a flock had something to do with their behavior.

  In the first week of January 2011, months after almost all insect-eating birds had gone south, I was cheered by two chickadee males’ calling back and forth at dawn. It was still about four months before the chickadees would begin nesting. These two males were perhaps a hundred meters apart and were easy to distinguish because one gave his dee-dah call (sometimes described also as fee-bee) at a higher pitch than the other.

  Nowadays the chickadees often seem to live on black sunflower seeds. A crowd of them at my birdfeeder in Vermont had consumed over a hundred pounds of the seeds per winter, and I could not imagine what they could have found as an alternative food source. But when I first began living at my cabin in Maine and put up a feeder full of black sunflower seeds, no birds visited it for weeks, although I met chickadee flocks almost every day I spent in the woods. I had no idea how many there were, or which ones lived and which died, or why.

  Survival strategies of black-capped chickadees have long been of interest, and being interested in survival myself, I thought this a worthy topic. Aldo Leopold had sought answers to the puzzle of how they survived the winter, and in his classic 1949 book A Sand County Almanac he described the chickadees that came in the winter to a birdfeeder at his farm in Wisconsin. He captured and marked ninety-seven of them over a decade and learned from recaptures that only three remained in the fourth winter and only one survived to the fifth. By noting the farthest points from the feeder where his birds were seen, he learned that the chickadees’ home range in winter was nearly a kilometer across. Leopold speculated that since the birds were well fed at his feeder, their most likely major killer was weather, and that the “genius” of the one that survived five winters was its ability to find shelter from the wind. However, he did not test the chickadees’ dependence on wild food, and I wondered if food was also key to their winter survival. Might their habit of staying close together as a flock, besides reducing their chances of being killed by a sharp-shinned hawk, let them share knowledge about ways to broaden their diet to include novel foods as they become available from one season to the next?

  Sunflower seed is a huge departure from chickadees’ normal summer diet of insects, and given the variety and changing abundance of insects, there is scope for genius in keeping track of and finding them. I have on occasion collected cocoons of the Promethia moth (Callosamia promethea) in the winter that had been torn open. The contents of just one cocoon might be enough food to sustain a chickadee overnight at sub-zero temperatures. But to find one of these cocoons would be a major challenge, because they are wrapped in dead hanging leaves. Additionally, they are as tough as leather, and to open one would require a sustained effort, involving not only knowledge and skill but also confidence and persistence. These cocoons are rare, and those of all insects differ. It is a challenge to become aware of the rare, the new, all in the context of the profound change of summer to fall, and fall to winter, and winter back to summer. It seems to me that to stay abreast of the changing spectrum and availability of potential food in order to remain year-round in the same several acres may require constant exploring and an ability to adjust to unpredictable realities. In many locations survival skills now include finding a birdfeeder.

  The feeder I put up at my cabin was at first an experiment; I wanted to find out if and when a chickadee would find it and feed there, and what would happen next. I was not confident that one would arrive soon, because chickadees remain in or near their home territory all their lives, and it was unlikely that any chickadee then alive in the nearby forest had ever encountered either a birdfeeder or a black sunflower seed. So what would induce any of these wild, un-suburbanized birds to visit an unfamiliar contraption, notice the little black objects in it, and hammer one open, thus discovering a new food source? And if one bird did clear all those hurdles and discover this food, would others come to eat it also? Might they learn from one another, resulting in a sudden influx of sunflower-seed eaters?

  I hung my birdfeeder loaded with sunflower seed from a branch of the white birch by the cabin door one December. I waited a month. No birds came. Maybe the location was wrong. I moved it into the woods about three hundred meters
away from the cabin. Two weeks later, it was being visited by both chickadees and blue jays. I transferred it about fifty meters in the direction of the cabin. Chickadees came to the old location, searched, and one found the new site within minutes and was immediately joined by others. I then moved the feeder another fifty meters, and they almost immediately found it there also. I had the impression that as soon as one bird found it, the others at the old position flew to the new. In less than a half-hour of several more steps they were all visiting the feeder now hanging on the white birch tree next to the cabin although at the original site they had ignored it for a month. I had hoped that the chickadees might tell me something about how they survive in the forest through the winter, and also about how they thrive even as their world changes from month to month. The birdfeeder experiment suggested that being in flocks might be part of their solution, because the birds were sharing their discoveries by learning from one another.

  The chickadees at my feeder in January 2015 appeared to be a flock of up to sixteen individuals, the maximum I ever saw there together. But another experiment showed that there were many more around. Over five days I made 131 counts of their numbers at the feeder, for a total of 708 chickadee sightings. I could identify two individuals—a partial albino with a white cap, and a bird with a thin strip of orange flagging tape on its leg—which together accounted for 15 of the 708 sightings. Thus, assuming that these two were representative of the rest of the flock, there were about ninety-four chickadees in total.