During all these years I never heard or saw a barred owl, perhaps because great horned owls kill them.
Owls are vocal mainly just before nesting time, which starts in midwinter for the great horned owl and a month or two later for the barred owl. The barred owl’s standard vocal signature, who-cooks-for-you, is well known. Much less familiar are its unearthly-sounding shrieks, like cackling, maniacal laughter. This caterwauling in the middle of otherwise silent nights has been compared to a crazy screaming. Wildcats or bears may come to mind as other possible sources of these sounds. Such a vocal display does not, however, seem to our ears an inducement to courtship.
From the total lack of owl sounds of any kind, I did not suspect that there were any owls at all in the woods around my cabin in the winters of 2011–2013. But then, during the night of April 3, 2013, I heard an “expletive hoot” (as I described it then). An owl was near! Of that there was no doubt. Given the woodland habitat and the vastly different calls of the saw-whet owl, it could only be a barred or a great horned owl. On several occasions I had heard blue jays scolding in the woods at what I thought might be an owl, but when I went to investigate, they stopped their commotion and I saw nothing, except once some freshly plucked blue jay feathers on the snow.
I wondered how an owl could survive in my woods at this time of the winter, when the snow was deep. How could it catch mice or shrews hidden under the snow? But proof of an owl’s presence came a day after the expletive hoot. On my way to get water from the well, a mere hundred meters from the cabin, I found an owl pellet on the snow under a maple tree. I could not remember ever seeing an owl pellet so large: 7.5 centimeters long and 3.0 centimeters wide. Was it from a great horned owl?
Curious about what this owl had eaten, I dissected the pellet, which to my surprise contained the front ends of five skulls of the short-tailed shrew, Blarina brevicauda, and their matching jawbones. The owl had swallowed five of the mouse-sized shrews. I could not be certain it had eaten anything other than their heads, though, because I saw no other bones. It looked as if this owl had a fastidious taste for brains, and also a systematic killing method, since each skull’s brain case had been crushed or obliterated.
Blarina are stocky shrews that are ten centimeters long without the tail. Like moles, they have no noticeable eyes and live in the soil or at least under the leaf litter, which was now covered by a foot of hard-packed snow. How could the owl have managed to catch even one of these shrews, much less five of them, in an obviously short time? I could think of only one place where this could have happened: at the birdfeeder stocked with black sunflower seeds that hung in the birch tree by my window.
Chickadees, nuthatches, and finches spilled seeds onto the snow, and I had seen the burrows and tracks of small mammals that had come up out of the snow to feed on the seeds. The owl could have perched here every night, and I would not have known! Was it Bubo?
It was too late in the year for great horned owls, and possibly also barred owls, to nest, but perhaps if one found a suitable home site it would remember and come back the next year. So on that same day I made a big bird box out of a hollow apple tree that I had saved when making my winter wood supply. I sawed a short cross-section of the trunk, notched a hole at the top, and attached pieces of board at the top and bottom plus one at the side with which I could nail the prospective owl house to a tree. I nailed it about six meters up in a red maple near where I had found the pellet. Its entrance was large enough to accommodate either of the two owl species.
Four months passed before I again heard any owl, and it was then not just one owl but two calling back and forth. It happened on August 29, which I came to refer to as “the night of the barred owls.” I heard the barreds’ unmistakable who-cooks-for-you, and it came almost directly from where I had attached the owl box. Another long session of back-and-forth calling, this one for an hour, occurred near dawn. There seemed to be excitement in the calls. Heavy rain and wind were coming from the east, and wind-tossed leaves were flying along the ground. Even an owl could not have heard animals rustling on the forest floor or seen their movements, so this pair’s excitement was probably not from catching mice.
The next night, around 1 a.m., I heard the owl right next to the cabin. It must have been facing me, because the sound was quite loud. This time it wasn’t the usual who-cooks-for-you, but a single very drawn-out whooo with an inflection at the end. Just one call—and about two minutes later, another. A long silence followed, and then, from a distance, a series of three similar whooos. Then silence again.
Why were the owls calling now, at the end of the summer, far beyond the nesting season? The timing did not fit with the standard notion of why and when owls vocalize: the “passionate throes of courtship.” Two birds were interacting, and they were conveying information. But what was it? I had no clue. From then on I took detailed notes every time they called, describing what they said, in the hope of discerning some pattern from which to decode their meaning.
At first it seemed possible to make progress in the decoding, because I heard the owls every night. All the way through September and into October, the near owl, and sometimes also a distant one, called at dusk, sometimes in the middle of the night, sometimes even in the middle of the day, but usually most vigorously just before or at dawn.
For weeks there had been an apparent harangue between my (the near) owl and another to the north. Then, from November through January, only the near one called, and rarely. But by February, just when I expected courting to begin, every night was silent.
In all those months I heard the weird shrieking that supposedly sounds like a crazy woman screaming only once, at dusk on October 4. An owl had called briefly at 4 p.m. from close to the cabin, and another had answered from a distance. The answering one came closer, after which the caterwauling started. Was it a showdown of territorial rivals, or a reuniting of mates? I had no way to explain the singularity of this vocal exchange. But then, much else about the owls’ conversations was singular as well.
Usually my owl was the initiator of vocal monologues or exchanges. On October 13 at dawn it made twenty-six calls in a row. Instead of the usual four-syllable who-cooks-for-you, each call consisted of two of these phrases strung together into an eight-syllable utterance. The owl had commonly used the eight-syllable pattern with the final syllable greatly prolonged into a long whooo, either rising or falling in pitch at the end, sometimes smooth and sometimes with a tremolo. But this time the closing inflection was absent. Four minutes after the twenty-sixth call, the distant owl, perhaps a kilometer to the north, answered with four similar calls. Then, in mid-afternoon in bright daylight, the near one called again, but only six times, and another answered immediately, but only briefly. The next dawn my owl made a call I had never heard before: a drawn-out multi-syllable screech that I described at the time as arrr arrr eeeah-oooh with a downward inflection at the end. On November 4 it made only two long whooo calls, and on the next night six. At 6 a.m. on November 21, from its usual place in the pines next to my cabin, it made twenty repetitions of the standard who-cooks-for-you, except that each four-syllable sequence was again double. The next morning at dawn it called ten times in the double who-cooks-for you. That afternoon the distant owl called, and about two hours later mine erupted with seven long one-syllable whooo calls.
After this I heard no owls for five weeks and thought that perhaps both of them had left the area. Little did I know that one owl not only was present but had probably been watching me around the cabin off and on for at least two years.
On January 2, 2014, I suddenly acquired ten new pairs of eyes. They belonged to ten University of Vermont students who had come from Vermont to take my winter ecology field course: Nikki Bauman, Mike Blouin, Michelle Brown, Kat Deely, Kyle Isherwood, Stephanie Juice, Holly Kreiner, Ali Kosiba, Maddy Morgan, and Andrea Urbano. As usual, every one of them saw something new that I had never seen, but it was Kyle who on our third day spied the barred owl. Perched about fifteen me
ters up in a pine tree behind the cabin, it just looked at him calmly. In late afternoon, when the whole class gathered by the tree, it was still in the same spot. As we gawked it peered down at us for a couple of minutes but soon, as if bored, looked off to the side.
We convened at the cabin that night as usual and cooked and enjoyed a supper of soup and fresh, delicious corn bread. Gathered around the warm stove and the hissing propane lamp, we swapped stories about our finds that day. For example, Mike had found bobcat and coyote tracks where we had heard ravens call at dawn. The owl was not mentioned until a student who had gone outside wearing a headlamp rushed back in and blurted, “The owl is here!”
The barred owl’s perch when it visited at the cabin. (Only one of the trees in the forest is shown here!)
We spilled out the door and looked up: there it was, perched almost directly above us. Even with all our chatter and with several lights now aimed directly at it, the owl didn’t flinch. In fact, it didn’t even look at us. It was looking down, seemingly undistracted, in the direction of the birdfeeder. I wondered: Was it looking for short-tailed shrews coming to feed on the spilled sunflower seeds?
I had seen barred owls in the woods before, but never one this tame. This one clearly had long familiarity with humans, probably mostly with me over the last year. It, rather than a great horned owl, was the likely producer of the owl pellet with five crushed Blarina skulls. I had not seen this owl before because, unlike the students, I go to bed immediately after dark—unless there is a good excuse to stay up. There was a good excuse now, and I hoped to continue to observe this owl into the future.
Five days later I heard it call from the pines before dawn. It made two long, drawn-out, high-pitched screeches that mellowed at the end. There was no response from the distance. And that would be all I heard from the owl for almost a month.
On February 5 I lay awake and at 10:45 p.m. heard the owl’s who-cooks-for-you three times. The call was clear, and very close. Proof: the owl was still in the area. But I was unprepared when, at dawn the next morning, I stepped out the door in a snowstorm and saw it perched in daylight on the same tree, same branch, same spot on the branch, and facing the same direction as when the class and I had seen it deep in the night a month earlier. Seeming to watch something on the ground, it paid me scant if any attention as I walked past it to the outhouse, and a minute or two later it was gone. But I saw its wing prints on the snow under the tree.
The owl returned at dusk, and again it perched on the same spot.
My journal entries about the owl at that time were little more than descriptions of the vocalizations I heard at night. I had not deciphered anything about what the owls were saying, except perhaps that there was much they did say. Nevertheless, I was thrilled to have made the acquaintance of a wild owl in its natural habitat. But a week later, on February 13, 2014, there was more.
Another snowstorm was on the way, and at dawn the temperature hovered around −10°F. A gorgeous deep blue sky was fading to green, and a line of orange appeared on the eastern horizon through a latticed black silhouette of maple trees as an incredibly bright morning star shone to the southeast. I peeked outside, as I now did every morning, to see if the owl was there. I had not seen or heard it for a week, and I didn’t see it now. I made a cup of coffee, reclined on the couch, and picked up the March issue of Running Times, which had an article about me by the writer Scott Douglas. I was amused or bemused to read that “the competitive record” from my 1957 and 1958 high school cross country seasons “is in Heinrich’s first journal, a 3x7-inch notebook that’s half running diary, half nature log.” I had lent Douglas my journal, and he included a quotation from 1957 that was not about running: “Apr. 21—Barred Owl eggs ready to hatch.” (Later entries suggest I meant incubate, a three-syllable word not in my vocabulary at the time.) I could not recall how, more than fifty years before, I had known the barred owl’s incubation schedule. But I delighted in the fact that in the present my barred owl was approximately a month from egg-laying time.
After high school, as a freshman in English at the University of Maine, I was forced to write weekly essays. Thankfully I remember only one of these efforts. It was about a pair of barred owls that I observed at their nest in an old basswood tree in the forest near Pease Pond, about twenty kilometers from where I live now. I found the nest during spring break, and was so entranced by all the sounds its occupants made that I hid in the woods and listened to them for several evenings in a row. If I had met a band of just-landed aliens from another planet, I could not have been more excited than I was about these owls. I now had something to write about, and I could not not write. I needed to record the owl details so I could savor them later, again and again. I had probably deserved the grades I’d received on my other essays, but I knew that this one rated at least a B. I was eager, for once, to get my paper back. Then the unthinkable happened. I was the only one in the class who did not receive his graded essay. When I meekly asked the instructor about my paper after class, he looked me straight in the eye, smiled, and said, “I lost it.”
I would give a lot to have that essay now, to awaken memories of those evenings at the edge of the pond in spring with the just-returned black ducks quacking in the evening light and the owls later calling. But no memories could top what I saw less than an hour after reading my journal entry of April 21, 1957.
As mentioned, I was reclining on the couch. A movement caught my eye, I glanced to the left, and there, no more than three meters away, was the barred owl perched on a limb of the birch tree. I watched it for about twenty minutes. From time to time our eyes would lock, then its gaze would return to the ground. It seemed very alert at times, and I talked to it; it must have heard me but was relaxed. Once in a while I saw it almost twitch with excitement as it leaned over and focused on something below my windowsill. Suddenly it leaned farther over, spread its wings slightly, then again settled back and relaxed. It had to be watching an animal that came and went. I got up to grab my camera.
I soon got to use it. Once again the owl tensed and leaned over, but this time it turned around on its perch, then wham-dived onto the snow and came up with a Blarina in its talons. In a few swift wing strokes it flew up to another birch, where it chugged down the shrew whole in a series of gulps.
Hoping to keep the owl around, I left a dead red squirrel on the snow below its perch, but night after night my offering remained untouched. On February 18, though, after a heavy overnight snowfall, an oblong groove in the snow showed that something big had plowed into the end of a set of deer mouse tracks; no tracks led away. Since the dead squirrel had not interested the owl but something moving had, I wondered if it detected potential prey by hearing, seeing movement, sensing heat (infrared, as some snakes do), or recognizing form.
The owl’s hunting pattern, so readily available for experimentation here, might give me the opportunity to investigate what cues it used to find prey. So now I had to catch rodents to feed my friend. The way to its brain would be through its stomach. Barred owls are perhaps unusually catholic in their diet and ways of obtaining food. Although mostly feeding on voles, mice, shrews, and birds, they have been reported to chase amphibians on the ground, wade into water to catch crayfish, and dive to capture fish. These prey animals all have one thing in common: movement. Movement, it seemed, might be the best if not the only way for a generalist owl to survive over a wide range of habitat used by a diversity of potential prey. But there were other possibilities. I would go first for the low-hanging fruit.
On February 22 my owl was on its usual perch on the white birch. I brought out of cold storage a dead short-tailed shrew I’d been saving for it. These Blarina, I knew by now, were acceptable game. I threw it onto the crusty snow to almost the precise spot where four days earlier the owl had successfully intercepted a mouse. Knowing it could see that spot from its perch, I watched closely. The shrew was black, clearly visible against the white snow. Would the owl pounce? I waited ten minutes, but no, i
t did not budge. I recalled that rattlesnakes find mice in the total darkness of their burrows by “seeing” their body heat; the snakes have infrared detectors (although not in their eyes). Might the owl also detect heat? I doubted it, but my doubt was irrelevant. Experiments and experience decide. So I retrieved the shrew, heated it on my wood stove, and returned it to the snow. Nothing happened. The owl sat still. Again I waited ten minutes, and again there was no response. So body heat was not the owl’s hunting cue. Having also eliminated recognition of form, I deduced that movement and/or the results of it, such as sound, were the most likely cues used by this owl.
I had confirmation that movement was a primary cue from a long-eared owl I lived with while a graduate student at UCLA. The owl perched unobtrusively all day and part of the night on the almost ceiling-high corner of a bookcase in the small apartment my new wife and I shared. An unsuspecting grad student neighbor came to visit. While sitting on our couch he absent-mindedly twirled his wristwatch on his index finger, and the owl struck his hand. To say he was taken aback is an understatement.
A naturalist and prizewinning writer told me that during the winter a barred owl in his rural Adirondack setting fed on chicken meat he put out to attract birds. It would have been surprising if a hungry barred owl had not shown up at his bait. However, it probably had not initially come to eat chicken. Meat of many kinds attracts shrews, voles, deer mice, and red and flying squirrels. Any of these animals running around would be manna for an owl. But this is not to say that owls do not eat chicken, either dead or alive. Learning is part of their foraging tool kit as well.
One Wild Bird at a Time Page 6