Solving the Piping Plover Puzzle
Piping plovers are famous summer residents of beaches and lakeshores--the most adorable argument against development and reckless recreation. Yet where many spend the winter has long been a mystery. Until now.
Under an early morning charcoal sky, I turn my face away from the salt spray kicking over the sides of a 27-foot skiff speeding through choppy waters. We are bouncing along toward the Joulter Cays--a group of about 30 low, sandy islands a few miles north of the Bahamas' Andros Island. I hunch down in my seat and glance at the other wet faces on this impromptu water-park ride: Caleb Spiegel, a U.S. Fish and Wildlife Service biologist; Hardy Eshbaugh, a botanist who specializes in Andros Island plants; and Sue Haig, a supervisory wildlife ecologist with the U.S. Geological Survey.
Haig, unable to find the windbreaker she thought she'd packed for the trip, is wetter than anyone. Water dripping off her chin, she nevertheless smiles--no doubt because she is about to see what she has been seeking for the past 30 years: a major piping plover winter hot spot, just recently discovered.
The leading authority on the tiny endangered shorebird, Haig has devoted her career to piecing together the piping plover's natural history and full lifecycle. "I went through every museum record, every Christmas Bird Count, every piece of information you could come by to figure out where people had seen these birds in the winter, because we knew we didn't have their winter range figured out," she says. She walked for miles on Gulf Coast beaches and southern Atlantic shorelines in search of plovers, but this is her first trip to the Bahamas. Despite some plover sightings over the years, searching anywhere in the Bahamas--with more than 700 islands and roughly 2,000 cays (reefs made from coral, rock, and sand)--was, she says, like "looking for a needle in a haystack."
A plump, sparrow-sized bird the color of bone and driftwood and with a black brushstroke encircling its neck, the piping plover is most often seen running along sandy shores, its legs moving so rapidly it looks like a toy that has been wound too tightly. The species breeds in three geographically distinct populations: along Great Lakes beaches, on northern Great Plains lakes and river shorelines, and on the Atlantic coastline from Newfoundland to North Carolina. Though piping plovers are relatively widespread, they're few in number. When Haig first began her studies in the early 1980s, biologists estimated there were only about 4,000 left.
Our skiff slows to idle a short distance offshore from a cay where Walker Golder and Matt Jeffery are standing beside their kayaks. Golder, Audubon North Carolina's deputy state director, and Jeffery, a senior program manager for Audubon's International Alliances Program, spent the past three nights camping on the Joulter Cays. By day they walked across mudflats and kayaked in the shallows, working their way from north to south while counting piping plovers and every other bird they saw.
From the beach, Jeffery, sunglasses resting atop his cap, his face sporting a scruffy beard, calls to us cheerfully: "Did you bring the coffee?" His good spirits spring from the 230 plovers he and Golder have seen thus far--"100 at one site!" Golder says--and they still have today to explore other promising areas.
The low-lying Joulter Cays, occupying 4,000 square miles, are ideal piping plover habitat. Low tide exposes great expanses of sandbars and mudflats where the plovers and many other shorebirds feed on tiny marine invertebrates such as worms, mollusks, and small flies. At high tide, shorelines that rim the cays' higher ground provide safe havens for roosting. With the tide ebbing, I look at the extensive flats, pocked here and there by pools of water. In the distance are glistening sandbars, ribbons of turquoise water, and the dark-green lines of mangroves that grow along the cays' edges. The sky--deep, blue, splotched with clouds--is a dome without dimensions. The horizon looks like a place we could walk to in a couple of hours.
Haig can't wait to start scouting for plovers. Golder points to a sandbar a couple of hundred yards away. "Let's look at the mudflats on the other side," he says. He picks up his spotting scope and leads the way. We tromp through mud the consistency of wet cement. I try to find the right stride for the ankle-deep goop, but every few steps one leg sinks in halfway up my shin. Within 10 minutes I've lost a snug-fitting water shoe. I squat down and fish around for it. As I tug the shoe out of the mud, I lose my balance, lurch forward, and get my hands in front of me just in time to avoid a mud pie in my face.
Golder and Jeffery have been slogging through mud like this for days, often dragging their kayaks behind them. Counting shorebirds in a tropical paradise sounds easy, but clearly it's not. The days are long, and when the biologists are not paddling kayaks or trekking through mud, they're standing for long periods in neck-ache positions as they squint through their scopes.
After an hour at the sandbar, Golder estimates that 900 or more shorebirds are roaming the flats beyond it. When the tide comes in, forcing the birds into a tighter crowd, he wants to do an exact count. As soon as the water is deep enough for the skiff's outboard, we settle in among the kayaks and daypacks. Our captain, Franklin Riley, a local man who knows how to navigate this shallow water, wastes no time in getting us to within a half-mile of a nearby cay. Golder motions toward the cay's beach: "That's the white stuff I want to get a look at." In knee-deep water, the biologists wade to a sandbar and set up their scopes. Golder, Jeffery, Haig, and Spiegel spread out and for half an hour stand like statues as they peer through their scopes. Among the gathering of shorebirds, they find 15 piping plovers.
Back at the skiff, we set off again for another site. When we get there everyone jumps into the shallow water and wades toward a sandbar, scopes over their shoulders. Here it takes an hour to count plovers, and the tally is better than expected: 81 birds in all. Although it is only mid-afternoon, by the time the biologists return to the skiff we must head back or risk getting stranded here as the tide recedes.
After dinner back on Andros that evening, Golder places a satellite map of the Joulters on the table and marks GPS readings for the latitude and longitude of each cay they visited. As he reviews the list of birds, he keeps a running count that totals 326 piping plovers--more than three times the number they spotted last year. It is becoming increasingly clear that any successful conservation strategy for ensuring a healthy piping plover population must include protecting the Bahamian islands and cays they frequent from a wide range of threats, including development, the spread of invasive plants, and sand-mining operations.
Just 10 years ago no one knew that the Bahamas were so important to plovers. A 2001 census recorded only 35 of them in the entire chain. The census, started 10 years earlier by Sue Haig, was part of a USGS-coordinated effort to count the entire U.S. piping plover population every five years. More than a thousand participants counted the birds on their breeding territories, then a few months later spread out across the core of the plover's known wintering area to do the same--walking the beaches from North Carolina south along Atlantic shores and across the entire U.S. Gulf Coast. But winter surveyors found fewer than half the plovers tallied during the summer censuses--a serious challenge if you're trying to conserve the species. Knowing what's going on mostly in the breeding grounds is "like being blind in one eye," says Haig. "If you don't know the full story, you're going to make mistakes in the measures you'd take to protect the birds."
Haig and others suspected that large numbers might remain hidden in the Bahamas, and in 2006 Sidney Maddock, working for Audubon North Carolina, along with local volunteers, mostly from the Ornithology Group of the Bahamas National Trust, set out to cover more of the region. The survey of 66 sites delivered 417 piping plovers. Encouraged by the results, in 2011 the USGS increased coverage of the Bahamas with the assistance of biologists from there, as well as the United States and Canada, and the total rose to 1,066 birds. If the results of recent banding studies (see map, page 51)--under the direction of Cheri Gratto-Trevor of Environment Canada--are any indication, almost all of the plovers that winter in the Bahamas hail from the Atlantic Coast, and the 1,066 represent nearly one-third of the coast's breeding population.
Understanding this link is one thing; seeing it is another. The mysteries and marvelous feat of migration quickly become personal. So it was that six months before my trip to Andros I stood on a Long Island beach, my binoculars trained on a nesting plover 75 yards away. I squinted, looking for the bands that would indicate this was a Bahamas bird.
Kerri Dikun, coordinator of Long Island bird conservation for Audubon New York, stood next to me with a spotting scope. She had spent much of her summer monitoring 36 plovers at six different nest sites, including two banded Bahamas birds. Dikun is one of a small army of hundreds of people from 70-plus government and nongovernment agencies and organizations that monitor and protect the breeding plovers each summer.
Up and down the Atlantic Coast, rapid housing development on beachfront property and increased recreational use of beaches beginning in the boom years after World War II have continued to encroach upon the plover's nesting sites, in the area above the high-tide line. But the program to protect nesting sites, begun in 1986 when the United States placed the piping plover on the endangered species list, has proved successful. Between 1986 and 2010 the Atlantic Coast population alone more than doubled, to 1,782 pairs, and the total population has reached roughly 8,000, a bit closer to the species' historical population, estimated to be in the tens of thousands.
And yet 8,000 birds hardly ensures the species' future. One need only recall the fate of another shorebird, the Eskimo curlew, whose populations plummeted in a matter of decades in the 19th century, from hundreds of thousands to a few dozen individuals. Indiscriminate hunting was not the only factor; loss of the grassland habitat the birds depended on during migration was another. Today the Eskimo curlew appears to exist in name only.
On my first day on Long Island, before looking for banded birds, Dikun was slated to check on some piping plover chicks that were close to fledging at Orient Beach State Park, on the northeast tip of Long Island. We drove two hours, then walked another two hours to the end of a peninsula, where a pair of the birds had moved their chicks some days earlier, far away from beachgoers. Dikun, a 28-year-old brunette, her hair pulled into a tight bun to keep it off her neck on the sweltering July day, raised her binoculars and scanned the beach ahead of us, watching for any movement among the stones and sand heaped up by waves.
"Here's where I begin to get nervous," she said. A fox had been roaming the peninsula all summer, which might explain why a week earlier one of the four chicks from this plover family went missing. Dikun stepped forward slowly. If the birds remained motionless, it would be nearly impossible to spot them. They can appear for a moment, run a few feet, then stop and simply disappear into the background like jigsaw puzzle pieces set into place.
"There," Dikun said. "There they are. And there are still three chicks." Despite the time it took to get to these birds, we watched them for only a few minutes. As ground-nesting birds, piping plovers are easily disturbed by human activity, and easy pickings for many predators. On our walk back, Dikun showed me one of the "exclosures"--a 10-foot-diameter cylinder of turkey wire--that are erected around plover nests to keep out raccoons, foxes, gulls, dogs, and feral cats, to name a few common predators.
Near the end of our walk back, Sue Wuehler, manager of Orient Beach State Park, picked us up in a four-wheel-drive park vehicle. We approached a roped-off section of the beach posted with "keep out" signs explaining that endangered species may be nesting in the area. A man, oblivious to the park vehicle approaching, casually lifted the rope and walked inside--to pick up some stones for his daughters he said when Wuehler asked what he thought he was doing. A short but pointed lecture followed. "People see mountains and forests and they think 'nature,'" Dikun later said, "but they don't think of beaches the same way."
The following day we visited several beaches in heavily populated areas, including a private beach open to club members only--and to two Bahamas plovers. One of the banded birds ("light green-black" for the band combination on its right leg) was alone, its nest lost to predators a few weeks earlier, but the second bird ("blue-red") was holding its own. Earlier, however, this bird and its mate had moved each time someone tried to set up a protective exclosure around them, beginning a new nest at every attempt. "We had to give up on the exclosure," Dikun said. "Now we're just hoping no predators get to them."
We walked east down the beach near the waterline, staying as far as possible from the roped-off nesting area. Dikun set up her spotting scope about 75 yards away. "An adult is still sitting on eggs," she said. "That's good."
In a few weeks this bird--all of two ounces--would likely set off on a 1,000-mile-plus journey back to the Bahamas and spend the winter near where it had been banded. If that's the case, it could fight the headwinds of bad weather, locate places to rest on beaches that have not been degraded by development or "beach stabilization" projects, dodge off-road vehicles, elude predators, and all the while stay on course over open waters.
Typically, the adults leave first, followed by the young, but there would be no young for "blue-red" and its mate. A couple of weeks after I'd left, Dikun wrote to say that a predator had made quick work of the eggs.
Something more insidious than a fox or feral cat is creeping over the beaches in the Bahamas, a shrub with thick, smooth oblong leaves: Scaevola taccada, commonly called white inkberry. This alien from the Pacific--often accompanied by another invasive exotic, the Australian pine, Casuarina equisetifolia--is covering the sandy place just above the wrack line, destroying much of the kelp-strewn area where the piping plovers rest at high tide.
Both plants are gaining a foothold in the Joulters. And as we look for plovers at several sites on North Andros's eastern shore, we find the invaders nearly everywhere. No one has been tracking the plants' spread, but Hardy Eshbaugh, a former Audubon board member who co-led field courses on Andros for Miami University from 1978 to 1995, is shocked by how many beaches have been taken over by white inkberry since he was last here.
One local business owner is trying to help combat the invading plants. Brian Hew, owner of Kamalame Cay, an exclusive resort that caters to celebrities, removed the white inkberry and Australian pine covering his resort's beaches. And the plovers came back. When we visited him, he and Golder wound up chatting about setting up observation stations for his guests and creating artificial islands where shorebirds could roost.
In the end, the trip's piping plover grand total is 461 birds, more than five percent of the species' total population. Finding this many birds in a few days (how many more are out there?) makes Andros Island and the Joulter Cays invaluable to the Atlantic Coast population.
A few weeks later Jeffery trades in his kayak for a seat at a board meeting at the Bahamas National Trust, a non-governmental organization commissioned by the government to run the national park system*. The new data help make a convincing case that efforts to preserve the Joulters will be key for protecting piping plovers--as well as the Bahamas' tourism-based economy. Andros Island and the cays surrounding it are among the world's premier bonefishing sites. As luck would have it, good bonefish habitat is good plover habitat. Bonefish, the Formula 1 race car among fish, provide what is often referred to as the ultimate saltwater fly-fishing experience (an experience that raked in nearly $141 million in 2009).
Shortly thereafter, BirdLife International, a global coalition of organizations from more than 100 countries, declared the Joulter Cays an Important Bird Area, signifying that the site's habitat is essential for one or more bird species. Perhaps the pristine beaches and sandbars, turquoise waters, and food-rich mudflats will remain untouched, lost in time. "The Joulters," after all, jokes Jeffery, "are right in the middle of the Bermuda Triangle."
*The story has been corrected to correctly identify the Bahamas National Trust as an NGO.
This story originally ran in the November-December 2012 issue as "The Plover Platoon."