One Wild Bird at a Time

by Bernd Heinrich

  Thread is a great tool for making a dead shrew move. With one end of a white thread tied to the shrew and the other end in my hand, I threw the shrew onto the snow, then pulled it along. Instantly the owl hunched over, launched, and came silent as a shadow directly toward the shrew (and me). It “caught” the prey almost at my feet, and in the light of my headlamp, as it looked up at me briefly, its eyes shone red. I pulled on the thread and the owl lifted off with the shrew in its talons. The thread broke, and after a flurry of silent wing beats the owl landed on the perch it had come from and gulped down its prize.

  At dawn the next morning the owl was back at the same spot.

  It continued to come many nights throughout the winter, and sometimes even on the brightest sunny days. To me it became like a pet, but with the advantage that I didn’t have to provide for it. On occasion, though, I eagerly did so, and it eventually began to take meat from the ground next to my feet. Often it came flying out of the woods to land on its spot on the birch as soon as I opened the cabin door. It had learned where and when to watch for me.

  March 31, 2014. A big temperature drop and a deposit of hard-driven snow from a northeaster had purple finches, goldfinches, mourning doves, evening grosbeaks, the first returning junco, and at least ten blue jays crowding the feeders. The crows were in pairs now, and I watched one carry a twig to a partly built nest in the crown of a spruce. The owl seemed to have left—I had seen no sign of it for weeks.

  April 1, 2014. A gorgeous clear and cold day. The snow crust was strong enough to walk on for the first time this year. There was no sign of a raven nest, but I saw a single raven fly to the nest site three times. The pair of crows landed near a roadkill deer, cawed, and left. A raven flew over. But the big event was at night. I awoke near 1 a.m. to caterwauling, opened the window by my bed to hear it more clearly, and listened to the barred owl calls I had not heard since fall, the familiar four-syllable sequence who-cooks-for-you (henceforth abbreviated as wcfu). Consecutive sequences were evenly spaced, at about one every half-minute.

  The owl continued with scarcely a pause until daybreak, with mostly the usual wcfu but sometimes the eight-syllable sequence I had heard the year before, made by doubling the wcfu and drawing out the last u into a long whooo with a descending tremulous pitch trailing off at the end. There were long pauses between these songs, but I kept listening. At around 4 a.m. the owl called from near the back of the cabin and another responded from the north trail, one wcfu almost instantly answered with another. The owls were answering each other so quickly that they sounded like just one owl calling. It seems that at least some of the wcfuwcfu sequences that I had always assumed were by one owl were instead duets! With this in mind, I listened for a nuance that I had not been conscious of before, and I got up and went outside to see if my owl was on its perch on the birch tree; it was not.

  Spring and summer came on schedule, with frequent hooting as well as weird cackling and screeches. Fall arrived in its glory of color, the leaves fell, snow came, and then there was silence. As the season slipped into the third winter since the owl had first arrived, there was no sign or sound of it. I missed it, and when outside in the evening or at night, I almost always glanced up or shone my flashlight to its perch on the white birch. The long nights got longer and the short days shorter, and I wondered if the owl would ever return. Perhaps it had lost its mate and moved on. It might have died; owls are frequent roadkill. Some years ago while driving through New Hampshire one night, I passed a seemingly dead barred owl, then in my rearview mirror saw what I thought was movement of a wing. I turned around, retrieved the owl, and put it on the back seat of my pickup truck. Minutes later it revived and perched next to me on the backrest of the passenger seat, where it revived fully. A rare occurrence.

  Finally the solstice arrived, with its promise of nature’s reawakening. I had in the meantime had my own good fortune, having found a partner who loved the woods as I did, in spring, summer, and fall, as well as winter. The snow was deep by then, and my partner and I decided to celebrate in a fitting way: with a big bonfire and toasts of red wine by its warm glow. I chainsawed dead dry branches for the blaze plus some green ones for sparks, piled them up, and with a match set it all off. A large flame shot up into the moonless night.

  We added green branches to the hot coals, and sparks flew up in a stream. As we drank a toast my eyes followed their incandescence upward, and there against the black sky I saw, highlighted by the fire below, the gray-white outline of a huge owl just leaving. With several beats of its great wings it flew over the cabin and into the dark woods. But it came back after the flames subsided. I tossed a slice of the venison we were having for supper onto the snow directly in front of us. The owl leaned over on its since long-used perch and with no further hesitation swooped by us to pick up the food.

  Surely it was the owl I knew, my friend from the year before, the one that had learned that what I tossed for it was food. It did not need to see fur or feathers, provided the meal came from me. The next day in the light, it swooped down and grabbed meat out of my hand. It continued to perch on the same large birch tree, the same branch, and the same spot on that branch where I had seen it countless times before. These behaviors could not have spoken more clearly who it was.

  In the moment of joy and mystery when I realized that this was “my” owl, which was back and would again be here for weeks, months, or maybe longer, I felt connected with all the moments of my past and now my prospects for the future.

  6

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  Hawk Tablecloths

  A PAIR OF BROAD-WINGED HAWKS, BUTEO PLATYPTERUS, comes every year from South America to nest in broadleaf forest adjacent to our Maine cabin. In 2011 the pair arrived on or near April 25, when I saw one of them perched in a black cherry tree at the edge of a hole I had dug years earlier. The hole fills with meltwater in the spring. This vernal pool has become a breeding place for wood frogs, spring peepers, and salamanders, and later in the summer it is also populated by leopard and green frogs, dytiscid and gyrinid water beetles, and of course larvae of dragonflies and mosquitoes. The hawk was hunting wood frogs, which, just as the last ice is melting in a warm rain, emerge from under the fallen leaves and travel to their breeding pools to mate and spawn.

  Broad-winged hawks return later than other local hawks, probably because they wait until frogs and snakes come out of hibernation. As the name “broad-winged” suggests, these hawks are not built for swift pursuit, but snakes and frogs are suited to a sit-and-wait hunting strategy.

  They also nest late. I had in the past climbed to photograph their nests and taken pictures of clutches of two or three eggs with their typical spots and blotches of chocolate, purplish, sienna, tan, and various other shades of brown. The eggs are a feast to the eye on their nest molds, which are always chips and flakes of tree bark.

  It seemed odd for a bird to use hard bark chips, let alone to favor beech bark chips to line the nest. Live beech tree trunks have a smooth, solid surface, so the hawks can get the chips only from dead trees with flaking bark.

  For several years the broad-winged hawk nests were located a few hundred meters down the slope from my cabin, in a tall sugar maple tree where it divides into a quadruple crotch. Soon after seeing one of the hawks at the vernal pool, or more often the pair circling in the blue late-April sky, I’d check to see if they would reuse the old nest or build another nearby. The old nest had not been used in the last two years. But now in 2011 I saw signs of activity around it again. The best clues were two or three ash twigs on the ground beneath the nest that showed light fresh wood at one end, indicating that they had recently been broken off a tree. The hawks were rebuilding their old nest.

  On May 21, when the beech leaves had been unfurled for several days and the matted dark brown leaves on the forest floor were sprinkled with gorgeous blue violets, purple trilliums, and white star flowers, I saw a hawk on the nest. From the rise of the hill where I viewed it through binoculars, it seemed d
irectly in front of me, peering over the nest edge, as I looked into its yellow eyes.

  Almost a month later, on June 16, she (the presumed female) was still on the nest. I had no particular inclination to climb to the nest; I had visited others before and the rewards now seemed less than the effort. But then company arrived from Cape Town, South Africa, and changed the equation.

  Greg Fell and Dean Leslie, two jovial visiting filmmakers from The African Attachment working for Salomon Running TV S03 E01, came to make a short film about my lifelong interest in running (it is available on YouTube under the title “Why We Run”). When they wanted to record me doing something outdoorsy other than running, I suggested that I climb a tree and proposed the maple with the hawk nest. If lucky I might see the baby hawks; I had never been close to a broad-wing nest with young. The filmmakers strapped a small video camera to my head so I had my hands free to climb.

  As I began to climb, the hawk sitting on the nest flew to another maple tree. It called several times but did not seem agitated even when I reached the nest. The large stick nest held one egg and one pure white downy chick that was surely the cutest baby bird ever hatched from an egg (it can be seen in the video clip). Under it lay—to my surprise—pristine fresh fern fronds. The baby cheeped feebly, as though begging for food. The camera recorded this, and my new friends from South Africa were pleased. To them the nest lining of fern meant nothing, but to me, seeing the ferns instead of the expected bark chips was everything, because I had never before encountered this way of lining a nest.

  The whole nest mold was lined with a huge fern frond that must have been placed there an hour or two before my climb. Under it lay another frond, slightly wilted, that had probably been there for a day or so. I was amazed and baffled to see fresh ferns, because the nest “should” have been totally finished a month earlier, before the eggs were laid, and with the usual dry tree bark chips as a foundation for the eggs. This was a puzzle, and I had an opportunity to solve it. I knew I would make more visits to this nest.

  I climbed to the nest nine times in the next thirty-five days, until the young fledged on July 22. The parents replenished the greens almost daily for a total of fifty-five green sprigs, averaging two new sprigs per day in the first three weeks. At first the greens were ferns, but on June 26 the nest was lined with matted-down and wilting green sugar maple leaves with another very fresh fern frond on top. On July 4 the whole nest mold was solidly lined with fresh green cedar sprigs and a sugar maple twig with four unwilted leaves that could not have been a day old. It was 2 p.m. and 80°F; the greens must have been brought in that morning. Unlike any other birds I knew, these hawks were continuing to “build” their nest after the young hatched and even as they grew, almost until fledging.

  Lining the nest with greens must serve a purpose (confer an advantage), since it involves a cost. In order to get the ferns, for example, the hawks had to collect them from the ground, and getting the cedar sprigs required trips to a grove at least a half-kilometer away. The composition of the nearest trees did not match the nest contents. Therefore, the birds had exerted choice.

  I thought I could eliminate several alternative hypotheses of what the greens might do. Greens would not camouflage white nestlings. They could not have been nuptial gifts for a mate since there was no more mating or mate choice during the nestling stage. Cushioning and insulation were also not likely explanations, because the materials were neither fluffy nor soft and if serving as cushioning should not have been laid over solid bark chips. Nor would they have been incorporated this late in the nesting season. Improving the nest structure for future use was excluded because the lining would retain moisture and hasten rather than retard decay. Aromatic medicinal plants, used to possibly kill parasites, another potential option, also seemed unlikely. To be useful, such plants should have been incorporated into rather than placed onto the nest, and in any case the hawks’ choice of non-aromatic maple leaves and rejection of readily available conifers such as pine, spruce, and fir would exclude that hypothesis as well.

  But there is often more than one advantage to any given act.

  The one consistent aspect of the greens the hawks chose was that they provided a flat, clean surface. Spreading a fresh layer of greens may be analogous to our spreading a clean tablecloth (if we ate our meals without using plates). Hawks often store surplus food in the nest; on one of my inspections this nest contained a fresh, half-eaten young woodcock as well as remains of red squirrel and grouse.

  Since these hawks nest late into the summer and bring meat into the nest in the hottest part of the year, fresh greens as lining could serve a hygienic function. A clean substrate would reduce the accumulation of bacteria and hence retard spoilage.

  A year later the pair built their nest in the fork of an ash tree, and in the subsequent winter friends and I built a blind in a large red maple twenty meters upslope of the ash to be able to see into the nest if the hawks reused it the following spring. The hawks returned and again hunted frogs at the vernal pool, but they did not use the nest where we had built the blind. Most gambles are lost, but they often generate observations that can provide opportunities for other investigations. The next time led to blue-headed vireos.

  7

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  Vireo Birth Control

  WE EXPERIENCED THE COLDEST NIGHT SINCE SPRING ON September 11, 2011. Temperatures dipped to 40°F. There was not a breath of wind under the clear blue sky. The red maple leaves were already half turned and most of the wild-growing apples had fallen from their trees in the woods. Robins, thrushes, and a flicker had picked all the chokecherries from the clearing, and most of the migrant birds were gone. The almost deathly quiet, compared with the raucous summer clamor, was deafening—until suddenly, around 8 a.m., I heard the slow, languid, clearly enunciated syllables of a blue-headed vireo in full song. The call did not come from the red spruces, balsam firs, and white pines alongside the clearing where the blue-headed vireos had lived in the spring and summer. Instead, this bird was singing from a lone white birch at the edge of the clearing near where a red-eyed vireo pair had nested in a sugar maple that summer. I had to look closely for its distinctive white eye ring to convince myself of what I was hearing. He (female songbirds do not sing) sang in the birch for a minute, then flew into the conifers in the nearby woods and sang for another half-minute, and then was silent.

  The brilliant burst of song made an impression because of the bird’s unusual visit to the clearing and the unusual time of year: I had not heard a blue-headed vireo sing since the spring. I immediately retrieved my sketch of the bird from the spring and made improvements. This was an extraordinary event, and I wondered if the song was a response to something significant for this bird. Why now, why here, why so loudly and emphatically, and why so briefly? Why did it feel like singing? Birds were migrating; perhaps this one was passing through and was staking it out as a possible nesting site for the next spring?

  April 17, 2012. The ground in the woods was still under snow, but the first yellow-rumped warblers were returning, singing their lisping songs and foraging in the tops of the now blooming red maple trees. Ruby-crowned kinglets were migrating through and occasionally breaking into their staccato song-chatter on this windy and 30°F day. But what made the day for me was a blue-headed vireo that arrived and spent most of his time at what I thought would be an ideal nesting place. All morning long he sang continuously, loud and clear, circling all around the clearing, and by mid-afternoon he ended up where I had heard him or another blue-headed vireo sing so beautifully the previous fall.

  After this I was pleased to hear his songs of short slurry whistles with their upward- and downward-inflected notes daily.

  Two vireo species live here on the hill. The red-eyed lives strictly in deciduous trees and does not return until late May, well after the trees have leafed out. Its loud and energetic song is a constant all summer until August. The blue-headed vireo comes back a full month earlier than the red-eyed, long bef
ore any broadleaf trees have started to break bud. Here in Maine it lives and nests in conifers. Its song is similar to the red-eyed’s except that it is slower-paced and is heard when there is still snow under the spruces and firs. The blue-headed vireo normally quits singing in early summer. But birds of any given species don’t always abide by the norm. I had seen blue-headed vireos nest low only in conifers, but in 2012 I found a nest in an unusually placed (most are in clearings) tall chokecherry bush near the sugar maple tree where the broad-winged hawks had nested. The outside surface of this nest was white from fluffy raptor down, rather than the paper from hornet nests usually found on both red-eyed and blue-headed vireo nests.

  One often comes upon the unusual serendipitously, by play, by involvement with something entirely different. At least that is how I came to see a case of apparent avian birth control.

  On May 11, still before the trees had leafed out, while following a sapsucker through the woods, I heard and then saw a pair of blue-headed vireos. They were keeping in touch by calling softly to each other. One of them flew to the trunk of a white birch, tore off a thin strip of bark, and flew off carrying the strip in its bill. Its mate followed, and so did I, hoping to find the nest. The birds were soon out of sight, and I searched in vain for their nest at every spruce and fir tree I passed. The long strand of bark was probably for use in the beginning of nest construction; according to R. D. James, the unmated male chooses a nest site and starts building the nest by looping strands of material over a horizontal forked twig. The female indicates acceptance of him by helping, and she adds the nest lining on the final two of the eight days of nest building.