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Setting the stage for conservation on a hemispheric scale.
If you visit a beach at low tide in the spring or fall, there’s a good chance you’ll encounter a unique group of transients, wheeling about and landing in sync, probing with bills of fantastical shapes in the invertebrate-packed mud, or resting, beak under feather, in moments of calm.
These visitors, a few of whom stay to breed at our mid-latitudes in the summer, are the shorebirds, a diverse group that includes sandpipers, plovers, and oystercatchers. The writer Peter Matthiessen called them “the wind birds” for their legendary migrations.
Every shorebird you see is vitally connected to a flyway, an aerial artery that surges twice a year as thousands of birds travel to and from their breeding grounds in the northern hemisphere. On the East Coast, these routes can extend up past the Arctic circle and down to the southern tip of South America. One famous bird, a red knot known as ‘B95’ or ‘Moonbird,’ spent decades commuting from Tierra del Fuego to an island at the top of the Hudson Bay — 9,000 miles each way, year after year, until he might as well have flown to the moon and back.
“A flyway is an evolutionary consequence,” says biologist Brian Harrington. “Through time, shorebirds have tested all kinds of strategies for living in perpetual summer, so to speak. Different species end up with somewhat different strategies, but it's basically something that has developed through natural selection.”
In 1974, while working at Manomet Conservation Sciences in Plymouth, Massachusetts, Harrington wanted to learn more about where shorebirds concentrate along their journey. Surveying the whole route was a daunting task for a single scientist, or even a group of them, so he recruited volunteer birders to stake out their own spots along the flyway and count.
By setting out to make an accurate census at least three times each season, and by doing their best to separate sanderlings from semipalmated sandpipers, willets from yellowlegs, and red knots from dunlin, these volunteers built a huge dataset. Harrington is retired, but the program he started — the International Shorebird Survey — just celebrated its 50th anniversary. One common species, the semipalmated sandpiper, has been counted along its southward migration more than 30 million times in the half century since the survey began.
Like most bird news these days, the shorebird report is dire. Despite more than a hundred years of legal protection, shorebirds are declining in North America, on the East Coast perhaps even more so than elsewhere. In 2023, a team of researchers published a paper that used fall migration surveys to calculate that 16 shorebird species have declined by at least 50% since 1980. Some, like the red knot, have declined by more like 90%. Looking at just the past three generations of each species, the trends are even more troubling.
“The counts of birds are going down,” says Paul A. Smith, a senior research scientist at Environment and Climate Change Canada and the lead author of the paper. “We can say that with confidence. The numbers of shorebirds on these beaches are going down. And that alone should be enough to raise concerns.”
Harrington was also an author on the paper, along with scientists from Manomet and the U.S. and Canadian governments. “We know the populations of many species of shorebirds are plummeting, and that's because something has gone very wrong somewhere in their life cycle,” he says. “And so our big need right now is to figure out where in that life cycle — breeding season, south migration, north migration, wintering area — where in that chain of life they are facing issues that are causing them to die.”
Many of us are familiar with the passenger pigeon and its dismal fate, chalked up in part to its popularity as a menu item: pigeon pie. But if you had gone to a market in Boston in the 1890s, you would also have seen red knots for ten cents a dozen. All up and down the Atlantic coastline, shorebirds were commodities to be sold, eaten, or sewed into hats.
To get a handle on why this is happening, researchers use all sorts of techniques to track shorebirds on their long voyages. Leg bands are a time-tested way to re-sight birds along their route, and newer technologies like tiny VHF (very high frequency), cellular, and satellite transmitters can record each flight path in granular detail.
People are also watching shorebirds closely on their summer nesting grounds. In Massachusetts, beachgoers see conspicuous evidence of this as they skirt fenced-off nesting areas for piping plovers, oystercatchers, and terns (a close shorebird cousin, like gulls and skimmers, from an adjacent family.)
Most species nest much further north, and Smith has spent 25 summers on nesting grounds in the Arctic. “I watched the abundance of ruddy turnstones at my study site go from 30 or 40 pairs in the study area down to just a handful,” he says. “So I've watched the decline in abundance happen in real time.”
It’s not the first time shorebirds have been in trouble, but it might be their most extensive crisis yet. The birds we see now returned to a small measure of abundance following a powerful set of laws and cooperative strategies up and down their flyways, including landmarks like the Migratory Bird Treaty Act and the Endangered Species Act, but their future depends on these agreements growing stronger, not weaker.
From the Brink and Back Again
Many of us are familiar with the passenger pigeon and its dismal fate, chalked up in part to its popularity as a menu item: pigeon pie. But if you had gone to a market in Boston in the 1890s, you would also have seen red knots for ten cents a dozen. All up and down the Atlantic coastline, shorebirds were commodities to be sold, eaten, or sewed into hats.
“I mean, you've heard the stories,” says Paul A. Smith, “The punt guns, shooting buckets of nuts and bolts at flocks of birds and then stuffing them into barrels. It's hard to even imagine that kind of abundance. And so it's obvious, with that baseline, that there's been a massive decline.”
Traces of that abundance remain as windows into what we might have encountered along the coast in the early 19th century. “At Johnson’s Mills in New Brunswick,” Smith says, “You can have 120,000 semipalmated sandpipers in an area not even the size of a soccer field. Just one on top of the other. At high tide, they're all right up against the shoreline. That's astonishing, that sight.”
Here one day, gone the next, shorebirds nevertheless have insinuated themselves into the culture of the North Atlantic for millennia. They’ve been given many names, which differ sometimes even from one state to the next. Waldo McAtee, a biologist in the early days of the U.S. Fish and Wildlife Service, had a side hobby collecting colloquial bird names, and for shorebirds he recorded a rich assortment.
People often referred to all shorebirds, collectively, as snipes, graybacks, sandpipers or marsh-birds. In Massachusetts, they could be peckies or peeps, in Maine sand-birds or sand-peeps. Further south, some names were less whimsical — in the Carolinas people called them sand-chickens and sea-chickens, or even “maggot-eaters.”
Names for the least sandpiper, the smallest shorebird, walked a tightrope between affection and utilitarian scorn; in several places it was known as a “bumble-bee peep,” evocative of its small size. But McAtee recorded another name for it in Virginia: “Gunwad.” Dunlin could be known as “simpletons,” and the semipalmated sandpiper, known as a “pennywinkle” in Virginia, might be nothing more than a “medium sea-chicken” in North Carolina.
Piping plovers, which I have the strongest affection for, ran the gamut from “tee-o” and “peep-lo” in Massachusetts, in imitation of their inquisitive call, to “butterbird” and yet another “gunwad.” (That one, as with the least sandpiper, seems to indicate some annoyance about a bird’s small size and what it might be good for.)
Looking down from the sky, the lingua franca of a shorebird is mudflat and salt panne — open beach and marsh with good visibility for approaching predators, a nutrient-packed substrate of mud and sand, and a safe place to roost at high tide. In other words, waterfront property.
A mixture of annoyance and affection still seems to characterize human attitudes toward shorebirds — annoyance on the part of some beachgoers at the restrictions imposed during the prime days of summer, and affection on the part of many others at the dance of small birds along the waterline and the way that huge flocks of them add to the tapestry of our most beloved landscapes.
The sudden, abundant visitation of shorebirds to our beaches, and their departure from them just as suddenly, feels magical. “As we contemplate that sanderling, there by the shining sea,” Peter Matthiessen wrote in The Wind Birds (available on Amazon), “one question leads inevitably to another, and all questions come full circle to the questioner, paused momentarily in his own journey under the sun and sky.”
Historically, the great mystery of where shorebirds go when they leave became a scientific quest for some people, but for a great many others it seems to have made shorebirds an abstraction, an almost meteorological event with no source or sink. Certainly 19th century Americans, who treated wildlife as if it would be around forever, felt that way especially about migratory birds. Year after year after year, they reduced a vast cloud of birds to just a wisp, and in some species, to nothing.
But as that crisis reached its crescendo, it catalyzed one of our first and most enduring international conservation laws. “There's a treaty between America and Canada,” says Smith. “Tariff-free, I might add. It’s been in place since 1918: the Migratory Birds Convention Act in Canada and the Migratory Bird Treaty Act in the United States. It's always been the case for migratory birds that we collaborate closely.”
Conservation at a hemispheric scale
A flyway is both a strategy for an individual species and an organizing principle for people who work with migratory birds. In 1948, the U.S. Fish and Wildlife Service created four administrative Flyways for waterfowl (ducks, geese, and swans) and other game species. Flyway Councils were organized with committees of experts from the U.S. and Canada to develop conservation plans and hunting regulations.
These government flyways guide research and resources up and down the waterfowl life cycle, funded by billions of dollars in license fees from hunting and taxes on firearms. State and federal agencies conduct aerial breeding counts in the “duck factory” in the northern Great Plains, bird banding operations across the country, and surveys of hunter harvests, which inform wetland protections and habitat improvements at stopover and wintering areas. When trends go down, there’s a well-developed system in place for decisive action.
One famous bird, a red knot known as ‘B95’ or ‘Moonbird,’ spent decades commuting from Tierra del Fuego to an island at the top of the Hudson Bay — 9,000 miles each way, year after year, until he might as well have flown to the moon and back.
This large-scale coordination and investment pays off. In the paper that made headlines a few years ago for reporting a loss of 3 billion birds in North America since 1970, waterfowl actually showed an increase in abundance of 50%.
“These flyway-level conservation plans have been very useful documents to guide shorebird conservation,” says Paul A. Smith, who also worked on the 3 billion birds study.
Shorebirds — except for woodcock and snipe, which are managed as game birds — were late to the planning party, and families like sandpipers and plovers have trended in the exact opposite direction. Some funding is diverted for them, but it’s much less than for waterfowl. Shorebirds do benefit from other laws, like those that protect wetlands and endangered species, but they didn’t get a national strategy until the early 2000s, when an effort began to integrate them into broader conservation goals.
In the meantime, much of the work on shorebirds filtered up from below, supported by a far-flung network of scientists and nonprofit conservation groups across the hemisphere, who in turn rely on passionate volunteers.
“One of the things that I've been so heartened by through time is the willingness of different players in different parts of the world to come together and work toward building a conservation strategy,” says Brian Harrington. “It's been a mutual effort by people from a whole bunch of different countries and a whole bunch of different educational backgrounds. It’s pretty amazing.”
One outcome of this work is the Western Hemisphere Shorebird Reserve Network (WHSRN), founded in 1985, which coordinates conservation at key sites up and down the flyway. It’s a community that includes places like the Great Marsh north of Boston and the barrier islands at Monomoy National Wildlife Refuge in Chatham, but also places like the largest lagoon in Suriname, where a big sign bears some familiar shorebirds along with the word “snippies” (Dutch, for snipe.)
On the East Coast, dots on the WHSRN map begin at the Bay of Fundy and continue down through the Atlantic states and the Caribbean all the way to Argentina, color-coded by how important they are for shorebirds (yellow for regionally important, blue for hemispherically important).
“I mean, departments of state haven't been able to come up with levels of cooperation like that!” Harrington told me, laughing. “The bottom-up strategy can take decades to put together. But I think ultimately it ends up being perhaps more embraced. It hasn't saved shorebird populations yet, but it's certainly moving in the direction of what seems to be needed.”
Finding problems, looking for solutions
So what do shorebirds actually need, and what are people doing on the ground?
Looking down from the sky, the lingua franca of a shorebird is mudflat and salt panne — open beach and marsh with good visibility for approaching predators, a nutrient-packed substrate of mud and sand, and a safe place to roost at high tide. In other words, waterfront property.
“The roosting place has to be something that affords wide open visibility,” Brian Harrington says. “To see raptors in time to get flying and then get up to speed, at which point they can evade any raptor. Open beaches are one of the few places where they can do that. And that, of course, is where people want to be.”
Birds’ present-day bid for this real estate is woefully cash poor, and relies on human brokers to co-sign against other more disruptive uses of the beach. Driving, boating, biking, dog-walking, and beach volleyball all take place in areas where shorebirds would prefer to rest or feed. And those are the low-impact options. Birds also compete with condo developments and mitigation projects that harden coastlines against erosion by erecting concrete seawalls and bulkheads.
A mixture of annoyance and affection still seems to characterize human attitudes toward shorebirds — annoyance on the part of some beachgoers at the restrictions imposed during the prime days of summer, and affection on the part of many others at the dance of small birds along the waterline and the way that huge flocks of them add to the tapestry of our most beloved landscapes.
Needless to say, “hardened” is the opposite of an advertisement for birds who evolved to exploit the soft mud and range of tides. A study last year estimated that 33% of the world’s sandy coastline has been made impermeable, with dire prospects for any beach that tries to move inland as the seas rise. Along the Atlantic flyway, shorebird habitat overlaps with the most densely populated areas of the Eastern Seaboard, and despite proposals to the contrary, houses don’t often migrate.
“Habitat is not just the presence of a beach,” Paul Smith says. “Habitat is areas that are suitable for use by the animals. So yes, maybe there's a beach, but it's covered with people and dogs and trucks. And so it can't be used. Are those acres available or not? If they're not being used by the birds then probably not.”
It’s clear that human disturbance can have a serious impact on shorebirds, especially at staging sites, where “they spend significant time to rebuild their body reserves and prepare for another long distance flight,” Smith says.
Harrington did some of the early research on how disturbance can affect birds physically. “We tried to get a handle on whether it was resulting in mortality in the migration that followed after they left Massachusetts,” he says. “Basically we were able to show that birds that were disturbed a lot weren't able to get up to a threshold weight and were disappearing.”
More recently, scientists have calculated precise and significant weight loss associated with disturbance, and quantified the extra calories burned by birds that are constantly spooked. Birds don’t get these calories back once they start flying, and they need all of the ones they have. In one West Coast species, the bar-tailed godwit, a single calorie sustains about 3 kilometers of flight.
There are now reliable estimates of flushing distance for various species, and hierarchies of which activities cause the most disruption. But the basic facts have remained the same for decades, even as human use of the beach has diversified.
One of the best shorebird habitats on the East Coast is Delaware Bay, which was the first site identified and protected by WHSRN. Its most famous patron is the red knot, possibly our most well-studied shorebird. Brian Harrington was involved in the early days there, too. “We started putting color markers on them,” Harrington says. “We did it in Massachusetts and we did it in Florida, we did it in Argentina. And we were able to see, just through the re-sightings of these colored banded birds, that virtually all of them were going through Delaware Bay on the North migration.”
“It’s what I sometimes call panmixia,” he says. It’s a term from genetics, referring to the random mixing of a whole population at once. On the one hand, the crab-egg bonanza in Delaware Bay is a blessing that brings nearly all the red knots in the East Coast flyway together at one big, nutritious rest stop. On the other hand, it’s a curse — human intervention, like an overharvest of horseshoe crabs, can just as easily make the bay into a bottleneck, where scarce resources limit the whole species.
Paul Smith told me, “It’s conventional scientific wisdom that for a relatively long-lived species like a shorebird that has a small number of babies and lives a long time, the survival of the adults has the dominant force on the trajectory of the population. But we don't even know that for sure. Ideally, step one would be to define where these bottlenecks are. We have the scientific ability to do that, and we’re in the process of doing that for some really well-studied species like the red knot.”
For some species, all we know is that some birds leave and don’t come back.
Fantastic Voyages
On Martha’s Vineyard and Nantucket, islands with more than 200 miles of sandy coastline between them, extensive beach habitat means large breeding colonies of shorebirds. Scientists there band some birds annually after they hatch. Oystercatchers get bands on both islands, and black skimmers get them on the Vineyard.
“We would never have known where our oystercatchers go without these big bands on their legs,” says Danielle O’Dell, Wildlife Research Ecologist at the Nantucket Conservation Foundation. “And they're being reported by the public all the time. So we collect the most amazing information about their wintering territories. Most of them go to Florida, but we've had a few of the juveniles turn up in really fun places like Nicaragua, El Salvador, and Mexico.”
“Then it's like a waiting game to find out if they ever come back to Nantucket,” she continued. “We definitely worry a lot about our birds in the wintertime, because we have no control over that. And the wintering grounds are often not as protected as the nesting territories.”
This data can reveal surprises, like when a 20-year-old Nantucket oystercatcher named F2 got blown far off his annual route from Polpis Harbor to Horseshoe Beach, Florida, and wound up in Kentucky, setting a rare bird record there. “It was a huge deal to the birders in Kentucky because they'd never seen an oystercatcher there before,” says O’Dell.
A more significant finding came in 2011, when surveys identified thousands of federally threatened piping plovers wintering in the Bahamas. These East Coast snowbirds are fewer in number than the human ones who make the same journey, but they represent 30% percent of the Atlantic population. Quickly following this discovery, a key part of their wintering habitat was declared a National Park.
“We had a plover that was banded in the Bahamas in the winter and nested at Dogfish Bar [in Aquinnah] for a few seasons,” says Luanne Johnson, wildlife biologist and director of BiodiversityWorks on Martha’s Vineyard.
“The ways that we can track birds have expanded exponentially in the last 15 years,” Johnson says. “It’s incredible, and it opens up a lot more possibilities.”
The black skimmers that nest at Eel Pond in Edgartown are the northernmost colony in their range. “You wouldn't have thought that skimmers would nest here 20 years ago, but here they are,” says Johnson.
“We decided that we wanted to start banding chicks so that we could track some of these birds and where they were going,” Johnson says. “We don't know their direct path of movement, but it seems that they follow the coast very closely and kind of hopscotch their way down. There are some people who re-sight our birds in Florida and email us. This woman, Ingrid Siegert, she's down in Key West, and she's got two that have been there the past two winters that she sends updates on.”
This can also lead to some friendly local competition. “We really, really want some of the Vineyard skimmers,” O’Dell says. “We know that they come and check out Nantucket pretty much every summer. And we know that some of our oystercatchers pop back and forth between the islands on a day-to-day basis. So, we're hopeful.”
Even very common shorebirds, like the willet, hold mysteries of their own. “We don't see eastern willets in winter plumage on the Atlantic coast, because they're gone — they molt after they migrate,” says Johnson. From 2013 to 2015, BiodiversityWorks tracked a handful by putting small geolocators on one leg.
“We would capture these willets, and then the next year we had to actually recapture that same particular bird and get the tag off and download the data. It was very hard to do because willets are so smart about predators, and they recognize us.”
The trackers, which use time and daylight to calculate latitude and longitude, revealed an incredible journey. “When they leave, they pick up and fly for three and a half, four days straight,” Johnson says. “They're airborne until they land in South America, on the northeast coast of Brazil. But on the way back north, they seem to be hitting South Carolina and North Carolina, not making a straight jump back to their breeding grounds. It's kind of amazing that they make these trips and then come back and nest within a few feet of where they nested last year.”
The willet, like many species, relies on the biological abundance of coastal habitats to flourish. “They're fueling up on fiddler crabs in our salt marshes to fuel their migration,” Johnson says. “Whimbrel too: fiddler crabs. Lots of crabs. I see flocks of semipalmated sandpipers out foraging in those salt marshes at low tide. There’s a tremendous amount of resources for them.”
“Lesser and greater yellowlegs move through here and feed,” she says. “Ruddy turnstones move through here both ways. And the semipalmated plovers, least sandpipers. Dunlin. All of those guys.”
Links in the Chain of Life
“The idea of birds going from key site to key site is the foundational concept of shorebird conservation,” says Paul A. Smith. “These birds come to these staging sites and spend a couple of weeks to fatten up and prepare for the next leg of their journey. Their annual cycle is just a linking of these site-to-site movements.”
“You can use banding information and modern statistical techniques to understand at what time of year the birds appear to be dying,” he says. “Are they dying during northward migration or are they dying on the breeding grounds? Are they dying during southward migration? We can try to piece that together with these mark-recapture studies that rely on volunteers to contribute their band sightings into the database.”
One thing is already clear: losing even one link in the chain of life can be catastrophic.
Attentive stewardship of nesting birds can make a difference. The American Oystercatcher Working Group coordinates an effort to increase reproductive success across the species’ breeding range, which has increased oystercatcher populations by 50% since 2008.
“You’re talking to a scientist. Of course I'm going to say more research is needed,” Smith told me. “There are things we need to understand better in order to target our actions efficiently. We still need to do something in the meantime.”
So what are the levers we can pull? “The best things we can do are the things that are within our control,” he says. “It is well within our control to reduce disturbance at key stopover sites. It is well within our control to ensure that foraging conditions for the birds are good, like with appropriate harvest restrictions on crabs in Delaware Bay.”
“And even if you determine that the lever you'd like to pull is climate change or something super hard,” Smith says, “maybe you pull easier levers first because you have more ability to pull them.”
For example, attentive stewardship of nesting birds can make a difference. The American Oystercatcher Working Group coordinates an effort to increase reproductive success across the species’ breeding range, which has increased oystercatcher populations by 50% since 2008. It’s an example of “improving what we can to account for the losses we can’t address,” says Smith.
In the meantime, the International Shorebird Survey continues, and is always looking for more volunteers. It’s an assignment more challenging than a backyard bird count, since the birds can appear in huge numbers and many of them are alike in stature and coloring. But it’s not so picky as to require a professional ornithologist.
“We want people to know the difference between a sanderling and a dunlin, basically,” says Lisa Schibley at Manomet, who coordinates the survey now. “I am a birder, and I actually started working at Manomet as a volunteer,” she told me. “Birders like visiting their local patches,” she says. “They know that the seasons will bring new birds, and then some birds leave. So go visit your local patch that has shorebirds, visit it at least three times in a season, and bird it the same time each day. And count all of the shorebirds. That’s the most important part.”
When the survey started, it was almost entirely volunteer, and it stayed that way for decades. That this data exists for scientists to use is an act of community, not an act of law. “It's kind of amazed me that thousands of people have been willing to go out and do the work that needed to be done,” Brian Harrington says. “I guess I'm somewhat floored by that. I always hoped for it, but I didn't expect it.”
What You Can Do
Check out the Audubon bird migration explorer.
Take a look at the trailer for an upcoming movie, The Flyway of Life, out at the end of April, 2025.
Download the Merlin Bird ID app for help in identifying birds. Once you’re comfortable with your IDs, use eBird.org to submit your sightings, which helps the Cornell Lab of Ornithology track migration patterns.
Keep your eye out for colorful leg bands and flags on shorebirds, and report them to the USGS banding laboratory. Read more about these markers here.
Be mindful of your presence and the presence of your pets on the beach, especially during the spring and fall. Here are some helpful guidelines from Mass Audubon on Nantucket:
- Always keep dogs on leash
- Drive slowly
- Don’t fly kites in shorebird areas
- Pay attention to all fencing and posted signs
Check out this graphic from the Atlantic Shorebird Flyway Initiative.
Learn more about the International Shorebird Survey at Manomet.
