Shorebirds, the World’s Greatest Travelers, Face Extinction

Dr. Fitzpatrick is director of the Cornell Laboratory of Ornithology. Dr. Senner is a scientist who studies migratory shorebirds.

A worldwide catastrophe is underway among an extraordinary group of birds — the marathon migrants we know as shorebirds. Numbers of some species are falling so quickly that many biologists fear an imminent planet-wide wave of extinctions.

These declines represent the No. 1 conservation crisis facing birds in the world today. Climate change, coastal development, the destruction of wetlands and hunting are all culprits. And because these birds depend for their survival, as we do, on the shorelines of oceans, estuaries, rivers, lakes, lagoons and marshes, their declines point to a systemic crisis that demands our attention, for our own good.

No doubt you’ve seen some of these birds while on vacation at the beach, skittering back and forth along the cusp of waves as they peck with their long beaks for tiny sand flies or the eggs of horseshoe crabs. They can seem comic in their frenetic exertions, tiny Charlie Chaplins in bird suits.

But these birds are remarkable in ways that defy not only belief but scientific understanding: They are, by far, the planet’s most extraordinary global travelers. Worldwide, about 70 shorebird species travel from the top of the world to its very bottom and back each year. The smallest weigh barely an ounce. Each species has its own story, but in every case these annual migrations are among nature’s most epic dramas.

Shorebird Migrations These two shorebirds, tracked by G.P.S. locators, migrated more than 6,000 miles in each direction.

Each spring, for instance, Hudsonian godwits depart from the southernmost coastlines of South America and fly north more than 9,000 miles to breed in the Arctic. Most make just one stop on the way — perhaps at a rice field in East Texas or a prairie wetland in South Dakota.

Outclassing Hudsonian godwits in long-distance travel are their close cousins, the bar-tailed godwits. Weighing barely a pound, they have made the longest continuous flights ever recorded for a bird. Individuals tracked by satellite have traveled nonstop more than 7,000 miles, flying for nine days over the Pacific Ocean between Alaska and New Zealand. To do this, a godwit must eat voraciously before flight. By liftoff day, it will have doubled in size, half its body weight a gas tank of fat.

Migrating godwits fly continuously through dark of night, buffeting winds and swirling storms, guided only by neural capacities packed into a hazelnut-size brain. To navigate, they may rely on sun and star alignments, a sense of the earth’s magnetic field and perhaps even a map in their brain of the entire Pacific, with its far-flung tiny islands representing visual way points.

Another shorebird, the pectoral sandpiper, departs from northern Alaska long before its offspring can fly, heading south to spend the winter in the pampas of Argentina. More amazing, the offspring left behind eventually take to the air on their own and, with no guidance, follow exactly the same route, joining their parents at a point 8,800 miles to the south. Scientists have no clue as to how this is programmed into the youngsters.

Populations of all three of these shorebirds are crashing. Since 1974, pectoral sandpipers have declined by more than 50 percent, and Hudsonian godwits have declined by more than 70 percent. The bar-tailed godwit may have lost half its global population within just the past few decades.

Declining Population Percent change among 19 species of North American long-distance migrating shorebirds +50 % 0 -50% -51% Range -100% 1975 1980 1985 1990 1995 2000 2005 2010 2015 Source: Environment and Climate Change Canada Declining Population Percent change among 19 species of North American long-distance migrating shorebirds +50 % 0 -51% -50% Range -100% 1975 1980 1985 1990 1995 2000 2005 2010 2015 Source: Environment and Climate Change Canada

Some shorebird species are already gone. Overhunting in the late 1800s decimated the Western Hemisphere’s Eskimo curlew. Its counterpart in the Old World, the slender-billed curlew, appears to have met the same fate a century later. Others are down to their last gasp. At least two dozen species that migrate from Alaska and Siberia to Australia and New Zealand are undergoing precipitous declines. The collective populations of 19 North American migratory shorebird species have fallen by more than 50 percent over the past 40 years.

The bottom line: Shorebirds are declining everywhere they exist, which is to say, all over the planet.

What’s driving these declines? Conditions are changing at multiple places across multiple continents, from northern breeding grounds to southern wintering grounds, and at essential stopover places, disrupting patterns thousands of years old.

Here is the migration journey for a bar-tailed godwit, traveling from northern Russia to Australia and back each year along the East Asian–Australasian Flyway. In the Arctic, where the climate is warming faster than anywhere else, the once-perfect timing of weather and breeding is going haywire. Rapidly warming early summers are igniting insect hatches before shorebirds incubate their eggs. By far the greatest threats facing long-distance migratory shorebirds lie at the mid-migration stopover sites — wetlands and rich tidal mud flats serving as crucial refueling stations for millions of migratory shorebirds. Areas along the Yellow Sea are being drained, dredged and filled in to create land for industry. More than 50 percent of the wetlands along China’s and South Korea’s coast have been eliminated. Tidal Loss, 1950s-2000s 100% LOSS 0 100% GAIN The 20-mile-long Saemangeum sea wall, which closed off an estuary along South Korea’s southwest coast, directly caused the loss of tens of thousands of great knots, about a quarter of the global population. Bird hunting remains rampant. Along the coast of China, illegal nets are erected every fall to capture shorebirds for human consumption. Shorebirds also face increasing threats to their southern wintering grounds, mainly from relentless coastal development and habitat loss. The coastal habitats where bar-tailed godwits winter are being invaded by a rapidly growing human population. One study found much of the intertidal shorebird habitats here are not within environmentally protected areas. HABITAT NOT WITHIN PROTECTED AREA Sources: Ying Chi Chang, Chris Hassell, Theunis Piersma, and the Global Flyway Network (bird migration paths); Planet (satellite imagery); Kiran Louise Dhanjal-Adams and others/Emu (Australian habitat protection map); Nicholas J. Murray and others/Frontiers in Ecology and the Environment (Yellow Sea tidal flat change map).

Population declines along the East-Asian Australasian Flyway have been so catastrophic that at least a few shorebird extinctions seem inevitable. The global population of Nordmann’s Greenshank is down to the last 1,000 individuals. Likewise, the spoon-billed sandpiper has the unfortunate distinction of being one of the world’s rarest birds — a tiny plush-toy of a shorebird with a bill shaped like a miniature dinner spoon that is now down to a couple hundred breeding pairs. This global population could be wiped out by a single typhoon.

Nests hatched per day, 2009 Nests hatched per day, 2010 Nests hatched per day, 2011 In 2009, Hudsonian godwit nests hatched closer to the start of insect season ... ai2html-settings settings_version: 0.69.1 image_format: auto write_image_files: yes responsiveness: fixed max_width: output: one-file png_number_of_colors: 128 jpg_quality: 60 use_lazy_loader: yes show_completion_dialog_box: true last_updated_text: headline: leadin: summary: notes: sources: credit: By The New York Times page_template: nyt5-article-embed show_in_compatible_apps: yes display_for_promotion_only: false constrain_width_to_text_column: false scoop_asset_id: scoop_username: scoop_slug: scoop_external_edit_key: Bird populations thrive when nests hatch before peak insect season. Nests hatched per day, 2009 Peak insect period 2 1 0 JunE 14 21 28 July 5 12 19 26 Aug. 2 Note: Peak insection period based on the highest average insect abundance. Source: Nathan R. Senner, Maria Stager and Brett K. Sandercock/Oikos In 2009, nests hatched at the start of insect season ... ... but in warmer years, nests hatched closer to the end Hatchlings thrive when born just before insect season. When this happens, there is not enough food for hatchlings. 2 3 Peak insect period 2 1 1 0 0 JunE 14 21 28 July 5 12 19 26 Aug. 2 9 JuNE 14 In 2009, Hudsonian godwit nests hatched closer to the start of insect season ... Bird populations thrive when nests hatch before peak insect season. Nests hatched per day, 2009 Peak insect period ... but in warmer years, nests hatched closer to the end When this happens, there is not enough food for hatchlings. Nests hatched per day, 2010 3 Peak insect period 2 1 0 Nests hatched per day, 2011 2 Peak insect period 1 0 12 19 26 Aug. 2 9 Note: Peak insection period based on the highest average insect abundance. Source: Nathan R. Senner, Maria Stager and Brett K. Sandercock/Oikos

Searching for any good news in this rapidly escalating disaster is difficult, but glimmers of hope are emerging as the crisis becomes more widely acknowledged. China recently announced strict regulations to rein in the destruction of these coastal habitats and carry out a restoration program in the Yellow Sea. That development followed a collaboration between the Paulson Institute, founded by former Treasury Secretary Henry M. Paulson, and the Chinese government on a plan to conserve those coastal wetlands.

In the United States, incentives provided through the farm bill, the largest source of government funding for habitat conservation on private lands, have encouraged farmers and ranchers to restore and enhance millions of acres of wetlands, which provide vital stopover habitat for tens of thousands of shorebirds. Along the Atlantic Coast, the long-term regional decline of American oystercatchers was reversed after the federal Fish and Wildlife Service set aside important habitat. Building on this success, the National Fish and Wildlife Foundation is expanding an initiative to increase populations of 15 other shorebird species by 10 percent to 15 percent over the next 10 years.

Shorebirds also require safe passage. Here again, there’s progress. Several years ago, two whimbrels being tracked via a satellite transmitter somehow survived a harrowing migratory flight through Hurricane Irene, only to be shot by bird hunters shortly after touching down for a rest in the West Indies. Afterwards, hunting of certain shorebirds was limited or banned by French-governed Guadeloupe and Martinique, and neighboring Barbados. In China, officials began enforcing no-hunting laws following a television news exposé about illegal bird netting.

These are promising first steps but we need to do more, fast, for our own good. Hurrricane Sandy was a reminder that natural seacoasts are good not just for shorebirds but also for humans, serving as buffers against powerful waves and storm surges. Damage from the storm was especially severe where natural shoreline habitats had been sacrificed to buildings.

The global collapse of migratory shorebird populations is much more than a calamity facing a group of exquisitely evolved birds. It also tells us that our global network of aquatic systems is fraying. If water is the world’s lifeblood and aquatic systems are its connective tissue, then the decline of the planet’s most spectacular global travelers signals a systemic illness that demands our attention and action.