Wild Life
12.24.2019

Standing Guard

The population of this critically endangered bird has stabilized thanks to the conservationists who look after them, but what happens if the caretakers leave?

Every December on the remote basaltic plateaus of southern Patagonia in Argentina, hooded grebes (Podiceps gallardoi) settle in to lay their eggs. Nearby, their personal guardians, field technicians charged with protecting the birds and their nests, stand watch. Armed with binoculars, flashlights, and shotguns, the guardians do whatever they can to eliminate threats to the grebes, although some perils are harder to see than others.

It is an extreme endeavor that requires both patience and warm clothing, says Ignacio “Kini” Roesler, a conservation biologist and ornithologist with Aves Argentinas, an environmental nonprofit in Buenos Ares, one of two main groups dedicated to protecting the hooded grebe. At up to 1,200 meters (3,900 feet) in elevation, the Patagonia steppe is a flat, open desert, dotted with more than a thousand glacial lakes, surrounded by rocky bluffs and framed by the Andes in the distance. The weather here is always harsh—windy and cold, even in the South American summer, when the hooded grebes build their nests on vegetation floating on the lakes.

The work of a colony guardian can be lonely. Other than a teammate or two for company, there is nobody around for hundreds of kilometers, and field stints in this harsh environment can last for weeks at a time. Despite the hardships, though, guardians are regularly reminded that their work is critical. “You are taking all this responsibility for the conservation of species,” Roesler says. “So, it’s pretty good actually—the feeling.”

With an estimated 800 to 1,200 hooded grebes remaining in the world, the species would be on the verge of extinction, conservationists say, if not for around-the-clock vigilance from colony guardians, among other rescue efforts. But such extreme actions also raise questions: Will conservationists be able and willing to maintain this vigil in the long-term? What will happen to hooded grebes if guardians stop showing up? And even with guardians in place, can the birds hang on in the face of such threats as climate change?

Protecting the hooded grebe is an exercise in hope that hints at the future of other endangered species, while testing the limits of how far people are willing to go in the name of conservation.

Santa Cruz, Argentina

Days of plenty

The hooded grebe was unknown to science before 1974. That’s when researchers made a surprise discovery while preparing bird specimens for a museum collection, says Santiago Imberti, an ornithologist and president of conservation for Asociación Ambiente Sur, an Argentinian NGO and the other major organization in charge of the hooded grebe conservation effort. What was thought to be a silvery grebe turned out to be a new species, and a new member of a group that now includes more than 20 species of grebes. Even within its family of freshwater diving birds, this one turned out to be exceptional.

About a foot long from head to tail and duck-like in shape, the hooded grebe has a white body, black patches on its back and head, and scarlet-red eyes, highlighted by a shock of orange feathers that spans its forehead like a bandana. To identify a new species of bird, and such a beautiful one, as late as the mid-1970s was enough to make it a rare and attention-grabbing discovery. But what makes the hooded grebe really stand out is its outstanding courtship display. When it’s time to mate, the birds pair up, chest to chest, and mimic each other’s’ head movements, bobbing and twisting in unison like a pair of Olympic figure skaters.

Overlooked for so long because of their remoteness, the birds are remarkably social, adds Ugo Mellone, a behavioral ecologist and wildlife photographer, who spent a month in Patagonia to capture the images in this story. “Sometimes, you are looking at them and they seem to be talking to each other,” he says, adding that, unlike other waterbirds in the region, the hooded grebes showed no fear of people. “There is a picture in which there are maybe four birds… and I remember it seemed they were chatting with us. They were always very noisy.”

The birds spend their summer breeding season, from December through April, on the highland plateaus of Santa Cruz province in the southwest corner of Argentina. The area looks like a cross between the Sahara Desert and the alpine lakes region of Europe, says Mellone, who donned a dry suit and slipped into frigid lakes to get some of his photos. The lakes and their volcanic-ash beaches are so rarely explored that the first researchers who tried to survey hooded grebes had to make their own maps.

One of those researchers, ornithologist Jon Fjeldså, was already a grebe expert at Copenhagen University in Denmark when he heard about the discovery of the hooded grebe in 1978. Three years later, he traveled to Argentina to see the birds for himself. Teaming up with American ornithologist Gary Nuechterlein, who was there working on a separate study, the duo visited the grebe’s only known location at the time, a lake where they initially tallied 74 birds. Over the next two years—without GPS, maps, or much in the way of roads, and only satellite images to help him locate lakes—Fjeldså returned to look for more.

This time, he hit the jackpot. In one lake, he counted 700 grebes. After finishing the surveys, he estimated a population size of 3,000 to 5,000 hooded grebes. Looking back at the data, Roesler thinks the true number was closer to 10,000.

The hooded grebe has highly specific needs, Fjeldså observed, and the environment here seemed to meet them precisely. Lakes on the plateaus contained dense floating vegetation, the only places where the birds would build their nests. The lakes also varied in mineral composition, with some containing large amounts of silica or salt. And they were flush with snails, insects and crustaceans for the grebes to eat. The birds had little competition for food. That was key, Fjeldså says, because hooded grebes collect prey one at a time to feed to the single young they raise in a season. If parents can’t find enough food, they abandon their chicks, so breeding seasons can be hit or miss.

Although its precise requirements theoretically made the bird vulnerable, that didn’t seem to matter much at the time, Fjeldså says. Hooded grebes may live for a decade, so if they have one bad year, they can generally make up for it the next. His surveys suggested that the birds were doing fine, and the International Union for Conservation of Nature (IUCN) subsequently categorized the species as Near Threatened—not in need of special protections. “I felt at the time that, OK, it will manage quite well,” Fjeldså says.

For more than a decade after that, Roesler says, monitoring basically stopped and researchers left the species alone. “They said that the grebe is not in danger because it lives in such a remote place and there are not many chances for humans to mess around with the species,” he says, adding that a population of 5,000 individuals seemed like “a comfortable number for a bird.”

Where have all the grebes gone?

When the lakes on the Patagonia plateaus begin to freeze in early May, hooded grebes fly via a still-unknown route to the Santa Cruz river estuary, a wildlife oasis along the Atlantic coast of Argentina, where they spend the winter months. In the late 1990s, Imberti began bringing high school students on field trips to the river and another estuary to learn about the birds by counting them.

The students, who won several awards for their work, have long since moved on. But Imberti continued with the annual censuses, and his observations have been alarming. In 2006, he reported that numbers on the wintering grounds had declined by 40 percent in just seven years. “We realized there was something really wrong happening,” Imberti says. “Numbers that had been seen in the 80s and 90s were simply not there.”

Finally, in the summer season of 2009–2010, 16 researchers, including Imberti and Roesler, mounted an expedition to the plateau to assess the plight of the hooded grebe. Using old maps and papers, they drove into the rocky, often-roadless desert, where winds gust up to 60 miles per hour and snow can fall in mid-summer. Even in a puffy coat, hat, and gloves, Roesler says he was cold much of the time.

The team searched for an entire week before they found any grebes, Roesler says. In multiple lakes where Fieldjsa had counted hundreds of birds in the 1980s, they now found none. Over the course of a month, the team visited 186 lakes and found 535 grebes in 14 of them—an 80 percent decline in just 25 years. Five lakes accounted for 85 percent of the population. The results caused “complete panic,” says Roesler, who was about to begin a PhD project on Andean birds and decided then to study the hooded grebe instead. “We thought there were 3,000 or 5,000 birds up there, and suddenly there were nothing but a few hundred. It was a little bit terrifying because nobody knew what was going on.”

The grim tally on the plateaus hit Imberti hard, too, confirming what he had suspected while monitoring the wintering grounds in previous years: Hooded grebe numbers had plummeted when nobody was watching. “When you get the numbers and you get the fieldwork done… and you realize your hunch is real, it’s really, really depressing,” Imberti says. “But it was also urgent. So there was no time to dwell about that.”

Horror show

As they set out to understand what was behind the steep population decline, the researchers found threats that were not just severe but also grisly.

In March of 2011, near the end of that summer’s breeding season, Roesler and Imberti visited a colony where everything seemed fine at first. The birds sat on their nests, looking content. The next day, the researchers returned to find a scene from a horror movie: Thirty-three birds lay dead in their nests. That added up to 4 percent of the global population of the species, all wiped out at once. “It was the whole colony, like they were frozen,” Roesler says. “They were still in their nests, but all dead.”

Grappling for an explanation, the researchers thought maybe someone had poisoned the lake. Then they saw it: an American mink (Neovison vison). Mink had lived in wild Patagonia since the mid-20th century, after escaping from fur farms. But they had never been seen in grebe habitat before this. A closer look at the dead birds revealed injuries on the back of the neck and head, consistent with mink attack. The grebes, normally preyed on by falcons and harriers, had been unprepared to face a predator that moved by land and water. A single mink, Roesler adds, was responsible for this relatively common type of predation, known as a surplus killing, in which carnivores kill more than they can eat, possibly to practice their hunting skills.

Mink expert Laura Fasola, who was working on a study of competition between mink and Southern river otters at the time, remembers hearing about the slaughter with dismay. As early as 2005, she had noticed mink moving closer to grebe territory, and it had occurred to her that the predators’ range expansion could end badly for the birds. The news filled her with remorse. “My reaction was, ‘Oh my God,’” says Fasola, an ecologist with the National Scientific and Technical Research Council, an Argentinian government research agency. “I really regret not being more emphatic about what I found in 2005.”

In response to the latest news, she did her best to make up for lost time, documenting the extent—and the timing—of mink movements in the region. In surveys between 2012 and 2016, she and Roesler found that mink were periodic visitors to the high plateaus, arriving in mid- to late-summer and overlapping with breeding grebes for just a couple of months each year. Although relatively brief, that period was a particularly sensitive time when juvenile grebes, most of whom had already survived predatory bird attacks and wind storms, were preparing to set off on their own.

After that first documented surplus killing, two more followed over several seasons, adding up to 75 grebes killed by mink. In a paper that reported the discovery of mink in grebe habitat, Roesler, Imberti, and colleagues warned that the predators could be catastrophic for hooded grebes. But mink weren’t the only problem.

Kelp gulls (Larus dominicanus), a native species that preys on grebe eggs and chicks, is another growing threat. According to a 2011 study, the number of kelp-gull breeding pairs in northern Patagonia had increased by 37 percent over in the previous 15 years. Since then, the researchers have continued to see gulls in hooded-grebe habitat, and they have seen grebes behaving defensively when gulls are around.

Since 1940, a growing aquaculture industry has also stocked highland lakes with rainbow trout (Oncorhynchus mykiss), which have caused all sorts of problems for grebes. The fish compete with the birds for food; large trout prey on nesting grebes; and fishermen unintentionally trap grebes in their nets. In multiple studies, researchers have documented changes in the composition of microorganisms in lakes after exotic fish are introduced, with subsequent and sometimes drastic effects on waterbirds.

Climate change is a growing threat as well, causing lakes to disappear—something the scientists have observed first hand over decades of research on the plateaus. “A lot of the lakes that used to be really good for the grebes in the 80s, now were completely dry,” Roesler recalls from an expedition in 2011.

Dramatic rescue

In 2012, after the team first documented the population crash, hooded grebes were re-classified by the IUCN as Critically Endangered. That same year, the first colony guardians arrived to do whatever they could to keep the birds alive and breeding. Since then, the routine has been more or less the same.

Each December or January, when the breeding season begins, teams of at least two guardians arrive at their designated lake to stand watch. There, they set up base camp, where they stay for 10 to 15 days before taking several days off and moving to a different lake—a schedule meant to combat monotony. Every day, between 7 a.m. and 7 p.m., guardians count all waterbird species, along with attacks on birds by invasive species. They patrol the perimeter of their designated lake to look for mink scat and tracks. They also bait and check mink traps.

If they see a mink, guardians are trained to hunt them down, typically at night. One person spotlights the animal. The other shoots. They also shoot Kelp gulls, which have thrived in the region because of poor waste management in populated areas off the plateaus.

 

Such unconditional devotion to the hooded grebe appears to be working. Between 2011 and 2015, guardians helped protect 10 colonies for a total of 755 days, and their presence boosted the birds’ breeding success by 50 percent. In unprotected colonies, breeding pairs raised an average of 0.39 juveniles, compared to 0.64 juveniles per breeding pair in colonies that were guarded by grebe-sitters.

While the guardians keep watch, Fasola has been leading an effort to prevent new mink from replacing the ones that are killed by guardians. Since 2013, she and colleagues have placed more than 100 mink traps in lakes around the Buenos Aires Lake Plateau, one of the highest and largest plateaus in Santa Cruz province, and they continue to expand the work. Now covering about 5,000 square kilometers (1,930 square miles) and 550 kilometers (340 miles) of rivers, the area overlaps with both hooded grebe habitat and important mink corridors. It’s a huge area, but mink stick to rivers and streams, Roesler says, so focusing their trapping efforts in those waterbodies should help prevent new invasions.

The floating traps, which look like simple plywood birdhouses and kill mink on entry, attract the predators with meat slices and mink pheromones, which, Fasola says, her team acquires by collecting anal gland secretions on fur farms. They check the traps every five days—an effort that requires long, bumpy drives and walks of up to 25 kilometers (15 miles). The work continues until about early May, when the birds once again migrate to their wintering grounds. So far, the project has removed more than 120 mink, and there have been no documented mink attacks on grebes since the summer of 2016–2017, when a mink killed two adults.

Eventually, Fasola hopes to create a haven for mink that would provide optimal conditions for them. Along with management to keep population density low, the hope is that young mink would stay put instead of striking out into hooded grebe territories. Known as an ecological trap, the strategy has been implemented in Scotland, in an attempt to control invasive mink there, with mixed results. “We’re shooting to get to the point where we don’t need to keep the mink away from the grebe because they just won’t want to go there anymore,” Fasola says. “They’ll be in a happier place.”

Other conservation efforts underway include trout removal—which has increasing support from local fishermen—and work with fishermen to shift their winter activities to avoid grebes. Public outreach has taken a creative approach, such as a theater production for kids called “Quien se ha robado mi nido? Macanudo problemo!” or “Who has stolen my nest? What a problem!”—a type of interactive educational project that gets communities invested in the birds. Habitat preservation is another priority. In 2015, Argentina officially designated Patagonia National Park, a 52,000-hectare (130,500-acre) protected area that incorporates the hooded grebe’s primary breeding habitat, including the lake where Imberti and Roesler found all the dead grebes in 2011. Imberti named that lake “El Cervecero” (“The Beer Drinker”), in honor of his late father’s favorite soccer club.

With protections in place, hooded grebe populations have begun to level off, and annual counts suggest a slight increase, Roesler says. During the summer of 2018 and 2019, his team counted 782 adults across six plateaus, up from 764 adults the year before and 749 adults the year before that. Those counts cover an estimated 95 percent of the population.

What no one can say for sure is when, if ever, the work of the guardians will be done.

What is success?

Hooded grebes aren’t the first birds to be the focus of such intensive, and drastic, conservation efforts, says ornithologist Scott Hecker, director of bird conservation at the International Conservation Fund of Canada, which funds the work of Asociación Ambiente Sur.

For years, Hecker spearheaded a project to save the piping plover (Charadrius melodus) along coastal Massachusetts. He started the work in the mid-1980s, when there were just 126 breeding pairs in the state, partly because people liked to drive on the beach, unknowingly destroying plover eggs and killing newborn chicks. Ongoing strategies to protect the plovers include restrictions on beach-driving, fencing around every nest, and a guardian program similar to the one in Patagonia. For weeks each summer in the town of Duxbury, Massachusetts, as many as 20 employees guard each plover nest throughout the day from the time the chicks hatch until they fledge. Traffic is restricted at night, when the guards go off-duty.

Although the piping plover remains on the endangered species list, its population in Massachusetts has grown more than five-fold to 650 breeding pairs since protections began—a successful outcome that makes Hecker hopeful for the hooded grebe. “That’s quite a spectacular recovery of an endangered bird,” Hecker says. “It shows that it is possible to turn these numbers around.”

Still, many uncertainties remain. The budget for Asociación Ambiente Sur’s work on hooded grebes is $80,000 to $100,000 annually, Imberti says—a significant amount for conservation work in Argentina. “Without continued help, hope for grebes would lower quite a bit,” he says. Meanwhile, none of their threats have been eliminated.

Mink have been moving closer to two more plateaus where grebes breed, Fasola says. Climate change is continuing to bring less snow and more wind to the plateaus, accelerating evaporation. And two hydroelectric power stations are being planned for construction on the Santa Cruz River, the grebe’s prime wintering grounds. Those dams could be devastating, Roesler says, threatening not just hooded grebes, but also resident dolphins, cormorants, and penguins.

For now, the colony guardians plan to carry on. The hooded grebe has become an icon for Argentina, a symbol of wilderness, and a source of pride in a rare and beautiful creature that people can rally behind. Although its future is in peril, Roesler says, he knows what would happen if people didn’t keep fighting for the bird. “What you can say is that if you stop doing all these conservation efforts, the bird is going to disappear,” he says. “All the threats are happening right now.”

Ugo Mellone

Born in Italy but based in Spain, Ugo Mellone works full time as a freelance conservation photojournalist. He received a PhD in behavioral ecology for his studies of raptor migration. His stories have been published by several magazines, including National Geographic. He has been a category winner in the Wildlife Photographer of the Year and speaker in international events. He also collaborates with wildlife film productions. To see more of his work, visit wildphoto.it or follow him on Instagram @ugomellone.

Emily Sohn

Emily Sohn is a freelance science journalist in Minneapolis whose stories have appeared in Nature, The Washington Post, NPR, Aeon, Discovery News, Hakai Magazine, and many other publications.

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