The Incredible Journey of a Migratory Shorebird

On a sunny June morning, in a bog outside Beluga, Alaska, I met a Hudsonian godwit. She had inky eyes and a long, slightly upturned beak that was pinkish-orange at its base and brownish-black at its tip. The feathers on her back were of mottled sepia tones, and those on her belly were rusty brown and painterly white. Her legs reminded me of the slender inserts of spring-loaded ballpoint pens, and her feet were refined pterodactyl claws. Her name (among humans) was A34, and she was about the size of a city pigeon. She was in the hands of Nathan Senner, a conservation biologist, who removed and replaced her geotag; measured her head, beak, wing, and leg; weighed her; and took two tail feathers and a sample of her blood. From that small number of data points, he can deduce where she’s been, how her feathers have grown, what genetic subgroup she belongs to, and her degree of exposure to mercury.Senner leads a research laboratory at the University of Massachusetts, Amherst, that is largely focussed on how migratory shorebirds, such as godwits, respond to environmental change. He grew up in Anchorage, where school loudspeakers announced the street corners on which moose had been sighted. In high school, he wrote an occasional “Birding with Nathan” column for the Anchorage Daily News. Senner’s father, Stanley, has devoted more than five decades to the conservation of migratory shorebirds. Starting in the nineteen-seventies, Stanley and his colleagues have been sounding the alarm on the vulnerability of shorebirds and working to protect key habitats, such as Alaska’s Copper River Delta. “Back then, no one was even talking about climate change,” he told me recently. Since 1980, roughly half of migratory shorebird species’ populations have declined by more than fifty per cent.Migratory shorebirds are usually not a person’s first bird crush. They lack the supernatural aura of the resplendent quetzal, and they don’t go in for outlandish mating displays like that of the prairie chicken. As the Princeton University biology professor and shorebird-lover David Wilcove put it, migratory shorebirds can give an impression of being “little brown guys, buzzing around in the mud, not too big and not too small, and, whether one is a stint or a phalarope or a knot or a godwit, they’re just kind of there.” And yet, Wilcove told me, they are a birder’s kind of bird. Once people get to know them, they tend to fall in love.Relatively few people have laid eyes on Hudsonian godwits. The birds mostly divide their time between remote northern bogs and muddy South American shores. John James Audubon apparently never saw a living one; he based his drawing of them in “Birds of America” on a few specimens he found in markets. Arthur Cleveland Bent, in a 1927 installment of his twenty-one-volume series, “Life Histories of North American Birds,” wrote of Hudsonian godwits, “I can count on the fingers of one hand the red-letter days when I have been privileged to see this rare and handsome wader.”It’s entirely possible that I had encountered A34 two months before seeing her in Alaska. In March, I had travelled from New York to Chiloé Island, in Chilean Patagonia. Flocks of Hudsonian godwits (the smallest of the four godwit species and the least well known) spend from roughly early October to April in and around the tidal mudflats there. The island also has Humboldt penguins, giant rhubarb plants with leaves as large as umbrellas, and the world’s smallest species of deer. Castro, the main town, is famous for its brightly painted wooden seaside houses, which rest on tall stilts to accommodate the tide. Homo sapiens is a shore-loving species. About forty per cent of us live within sixty miles of a coast.Chiloé is where Hudsonian godwits spend their non-breeding season and express their non-breeding personality, which is intensely gregarious and food-oriented. If you walk at low tide on the mudflats of Pullao Bay, you will see godwits bobbing for bivalves and worms, dunking their beaks in and out of the ground as if they were darning. They share their feasting grounds with oystercatchers, ducks, whimbrels, greater yellowlegs and lesser yellowlegs, and other shorebirds that neither I nor my Merlin Bird ID app could identify. The longer I watched the shorebirds on Chiloé Island, the stronger my impression was that they were dressed for a masquerade or a carnival, with some wearing stout beaks, some slim ones, others elegantly curved ones. The pale bellies and darker backs of many of the birds made it look as if they had on fashionable capes over slender, hosiery-clad legs. They called out to one another and occasionally broke into cotillion-like flight. The Hudsonian godwits appeared eternally committed to these revels. There was no sign that they were about to fly nearly ten thousand miles to Alaska, a wondrous and mystifying migration that one scientist called “technically impossible.”Birds are in trouble. Migratory shorebirds are in especially bad trouble. And long-distance migratory shorebirds, like the Hudsonian godwit, may be in the most trouble. “Birds are sentinels,” Stanley Senner told me. “The ecosystems they rely on are ecosystems we rely on as well, though it can take time to convince people of that.” Studies show that, without shorebirds, coastlines erode more quickly, trap less carbon, and are more likely to become unbalanced. In the Yellow Sea, for example, shorebirds feed on crabs whose population needs to be kept in check, as they graze on native vegetation. In some ways, shorebirds are analogous to the wolves that hunt the deer and elk populations that eat the tree saplings that become the trees that beavers use to build dams that help the fish—and so on. Shorebirds also transport and disperse essential seeds and nutrients. Our interests align, as they say. Also, like all birds, they are lovable, alien, awesome, and alive. Not long ago, I saw a dead magpie on a country highway. Other magpies gathered around it, as if saddened and confused. When a car approached, they scattered. After the car passed, they returned to their fallen friend. So there’s also that.To protect birds effectively, we need to understand them. So much about godwits remains unknown, including where and when they encounter their most mortal threats. Since their epic migration is maybe their most difficult-to-fathom characteristic, we may as well start there.“We shouldn’t have waited so long to have a baby.”Cartoon by Jon AdamsThe story of bird migration, as narrated in Western civilization, often begins with Aristotle, who wrote that, in the winter, redstarts turn into robins and garden warblers turn into blackcaps. This sounds silly but, compared with the idea that a caterpillar becomes a butterfly, it seems reasonable. Olaus Magnus, a sixteenth-century Swedish priest, argued that barn swallows disappear in the fall because they hibernate at the bottom of ponds. That also seems absurd until you learn about the common poorwill, which resembles an old piece of bark and spends months of winter nestled almost imperceptibly in the crevices of logs or among piles of rocks. This wasn’t scientifically documented until 1948, although the poorwill has long been known to the Hopi as hölchoko, “the sleeping one.”The Maori tell a story about how a godwit showed their ancestors the way from their ancient homeland of Hawaiki to New Zealand, more than a thousand miles away. But, to most people, avian migrations of that length were long unimaginable. In 1822, a hunter near the German town of Klütz shot down a stork; when he collected the bird, he saw that it had a wooden spear through its neck, later determined to be of African origin. Hunters eventually found more such Pfeilstorchs (arrow storks), giving credence to the hypothesis that the white stork not only migrated but did so between Europe and Africa. In some ways, this was a downgrade: the seventeenth-century minister Charles Morton, who wrote a popular physics textbook, claimed that birds migrated to the moon. He supposed that they fuelled a sixty-day flight there with body fat (reasonable) and that the journey was made easier by the minimal atmospheric resistance in space (also reasonable).Migratory birds in captivity develop Zugunruhe, an agitated fitfulness, at certain times of year. Scientists don’t know precisely what provoked A34 to set off northward one spring afternoon, with a flock of her fellows, though, if they did, they might better know how her species will be affected by the shifting seasons of our changing climate. Godwits cannot soar like hawks or glide like albatrosses. They migrate by continuously flapping their wings. They must navigate crosswinds and headwinds, storms and maybe an occasional hurricane, continuing on day after day, night after night. As best as we can tell, they do not, while flying, eat or drink or sleep (at least not with more than one hemisphere of their brain at a time). After a journey of hundreds of hours and thousands of miles, they descend on a snow-covered shore at the Cook Inlet of southern Alaska or another favored breeding ground. They land considerably lighter than when they took off. “Many arriving shorebirds seem to be tired,” the ornithologist and conservationist Joseph Archibald Hagar wrote, in his foundational monograph, “Nesting of the Hudsonian Godwit at Churchill, Manitoba,” from 1966. In a field-diary entry, Hagar describes a group of birds that “within a minute or two dropped into some sunny spot out of the wind, tucked heads into scapulars, and went to sleep, not to move again for as long as we watched.”In 1976, the young ornithologist Robert Gill took a job with the U.S. Fish and Wildlife Service in Anchorage. He was dispatched to the Alaska Peninsula to do biological inventories on public land that was up for lease to private companies. During those long-lit Alaskan summer days, walking across salt marshes and through the foothills of the mountains, Gill