Winged Warnings: Empty nests of the North
"Massive chick deaths" in seabird colonies; climate, oceanic changes blamed
FLATEY ISLAND, Iceland – When the days grew long, seabirds flocked to this hamlet on the edge of the Arctic to rear their chicks under the midnight sun.
"Kria," shrieked the terns, calling summer up from the slumbering ground. Black cliffs were transformed into snowbanks of white kittiwakes. Puffins whirred between land and sea. Murres plied the shoreline, fulmars patrolled the skies. Everywhere sounded their vibrant chorus.
These days, a scatter of stubborn holdovers streaks the sky and paddles the bay, but the legions are gone. The chicks have perished, their bereft parents have returned to sea.
Half of Iceland's seabirds nest on this low-lying volcanic outcropping and its neighboring islands in the deep west coast gash called Breidafjordur Bay. Flatey Island used to be covered with chicks snuggled inside rocky hillside burrows, under tall meadow grass, in nests strewn across headlands and shores.
Ornithologist Sverrir Thorstensson bands a seabird on Klofningur Island in Breidafjordur Bay.
Iceland, circled by the food-rich currents of Atlantic, Arctic and polar waters, is the Serengeti for seabirds. Its rocky coast, hillocky fields and jutting seacliffs are breeding grounds for 23 species, hosting an indispensible share of Atlantic puffins, black guillemots, great skuas, northern fulmars, razorbills, black-legged kittiwakes and more.
But the nests have gone empty in the past few years, and colonies throughout the North Atlantic are shrinking.
The suspected culprits are many: The leading candidates are the profound changes underway in the world's oceans – their climate, their chemistry, their food webs, their loads of pollutants.
Warming oceans and earlier thaws are driving away the seabirds' prey, unleashing deadly, unseasonal storms and knocking tight breeding schedules off-kilter. Mounting carbon dioxide absorption and melting glaciers are acidifying and diluting the aquatic balance, jeopardizing marine life and creatures that depend on it for food.
Alarmed scientists have returned from fieldwork throughout the North Atlantic with sobering descriptions of massive chick die-offs and colonies abandoned with eggs still in the nests.
"Mass mortality of kittiwakes is evident," said Freydis Vigfusdottir, a post-doctoral researcher at the University of Exeter in Cornwall, England. "You can see in the late summer lots of 'chick pancakes' in the nest."
And in the Arctic tern colonies she's studied, "there are just dead chicks everywhere," she said. "Not only do you have to provide your field assistants with food and shelter, but also some psychological help after many, many days of collecting dead chicks."
Total breeding failure
On Flatey Island, the once-prolific terns haven't produced viable chicks in more than a decade. More than half of the region's black-legged kittiwake nests vanished over 15 years.
And on the Westman Islands off Iceland's south coast – home to the world's largest Atlantic puffin colony – breeding has been a "total failure" since 2005, according to the South Iceland Nature Center. The impacts are being felt throughout the country, where these clown-faced birds have been both a legally-hunted delicacy and a national mascot. "Puffin watch" – news on how things are going in the burrows each summer – is as popular here as "volcano watch."
These cliffs on Breidafjordur Bay's Hafnarey Island used to be covered with kittiwakesCheryl Katz
Similar trends are reported in Scotland, the Faroe Islands, Norway and across the circumpolar north – the principal nursery for Northern Hemisphere marine birds. Most of the biome's species, the 2013 Arctic Biodiversity Assessment finds, are in decline.
"There are just dead chicks everywhere. Not only do you have to provide your field assistants with food and shelter, but also some psychological help after many, many days of collecting dead chicks." –Freydis Vigfusdottir, University of Exeter
Whole populations haven't collapsed – at least not yet. These hardy seafarers are long-lived, and millions of them still sail the North Atlantic. Normally, seabirds can withstand a few bad breeding seasons. However, reproductive failures have been going on for so long now that scientists say it's just a matter of time before the adults, too, are gone.
Now researchers are struggling to comprehend the catastrophic breeding failure and its implications for an ecosystem that is fundamental to the planet's health.
The seabirds' plight "is a huge concern ... not just in the North Atlantic but also globally," Vigfusdottir said. The cold waters of the North Atlantic are a major driving force for the Earth's weather and among the most productive fisheries in the world, so the birds' problems could indicate trouble for the region's major industry and the global food supply.
The suspected culprits of empty nests are many: The leading candidates are the profound changes underway in the world's oceans – their climate, their chemistry, their food webs, their loads of pollutants.
These same problems also are now being noted in wading birds like redshank, shorebirds like red knot, and other waterfowl in the northern United States, United Kingdom and elsewhere.
"What is happening in Iceland, we see happening in so many other areas in the North Atlantic. And the fact that we're seeing them over such a wide area points to a common factor ... and that is climate change," said Aevar Petersen, a retired Icelandic Institute of Natural History ornithologist.
Winds and currents funneling pollution northward from Europe, North America and China bring more bad news for seabirds preying high on the food web. Mercury, which damages birds' brains and reproduction, is ubiquitous – and rising fast in some areas. Brominated flame retardants, perfluorinated coatings, pesticides, plasticizers, polychlorinated biphenyls and more are contaminating a variety of species and locations. And masses of chemical-laced microplastics could be released by melting ice sheets.
Seabirds "are critical for detecting changes that are happening even more rapidly than we suspected," said Jennifer Provencher, a Ph.D. student at Carleton University in Ottawa who examines colonies in Arctic Canada. "We are getting basically a year-to-year-to-year update of the health of the oceans and the health of the environment through these seabird studies."
Aevar Petersen logs data while Ragnar Olafsson holds an Arctic tern chick on Flatey IslandCheryl Katz
It's likely all these threats are adding up, she said, sounding a warning across the north. "They're alarm bells, in real time, of changes that are going off."
Thick-coated sheep bleat as Erpur Hansen trudges across their steep pasture overlooking the sea. This is Heimaey, one of the 15 volcanic stacks lying off Iceland's south coast that comprise the world's most important breeding ground for puffins: The Westman Islands. Hansen, a biologist with the South Iceland Nature Center, is Iceland's de facto puffin prophet: Twice a summer he rounds the country to tally eggs and chicks and announce whether their breeding seems headed for success or another year of failure.
Hansen stops at a small, rocky hollow peeking up through a dome of wet grass. He dons dark goggles and, looking like a welder conducting a medical exam, snakes a flexible pipe with an infrared camera into the opening. Puffins nest underground, and this "burrow camera" lets him see inside without disturbing the birds.
"Nothing there," he says after a minute, and moves on.
Heimaey is in the Westman Islands, the world's most important puffin breeding grounds.
The burrows should be bustling on this July day: The Westmans are one of Iceland's three "mega-colonies." More than a million pairs of various seabird species nest here, including around 830,000 puffin couples. Puffins are loyal to their breeding grounds, returning to the same site year after year. The majority of the world's puffins breed in Iceland, nearly half of them here in the Westmans. The area is crucial to the birds' future.
But Hansen and colleague Ingvar Sigurdsson find burrow after burrow empty. If the chicks die, or the eggs don't hatch, adults leave the colony early and go back out to sea. "There hasn't been a proper chick production in 12 years now," Hansen says. And for the past nine years, hardly any have lived long enough to leave the nest.
Finally, success: A lone adult is at home. Sigurdsson pulls out a grunting bird with a parrot-like orange beak and lays it on its back. Dark triangles stare up from its Kabuki-white face as Sigurdsson measures, draws blood and plucks a few feathers, before letting it scramble back into its burrow. From this, the researchers will determine the bird's health and diet, and try to learn where it's been going to feed.
Rising ocean temperatures are squeezing out the birds' main prey, pencil- shaped fish called sandeel. For hundreds of years, sandeel were abundant in these waters, providing the intense nutrition chicks need for quick growth in the short northern summer.
Warmer waters seem to disrupt the sandeels' growth by speeding up their metabolism, Hansen says. Plus, more southerly fish, like voracious mackerels, are moving in. Puffin parents must forage farther and come back with less – or less-nourishing – fish for their young. These days, chicks starve, nests are abandoned, and increasingly, birds don't even bother to breed.
The sun is still high when the researchers call it quits that evening. Their arms are covered in mud, and on top of that, Sigurdsson wears the fishy smell of puffin guano. "Ja, we study the poo as well," Hansen says. But they've found no chicks this day, and very few adults. Hansen saw worsening conditions nearly everywhere on his puffin tours this summer.
"What is happening in Iceland, we see happening in so many other areas in the North Atlantic. And the fact that we're seeing them over such a wide area points to a common factor ... and that is climate change." – Aevar Petersen, retired, Icelandic Institute of Natural History
This cycle has occurred before, Hansen says later, at his house in the quaint, 4,000-person town on Heimaey. His analysis of historic weather and puffin hunting records has linked population dynamics to a periodic warming cycle called the "Atlantic Multidecadal Oscillation," or AMO.
Erpur Hansen and Ingvar Sigurdsson examine a puffin on Heimaey, in the Westman Islands.
Repeatedly, waters around Iceland have warmed for a few decades, then cooled for a few, and seabird populations have slumped, then recovered. The current warming cycle began in the late 1990s. But this time, Hansen's research shows, things are different.
"If you look at the AMO cycle, it's trending upward," he says. Ocean temperatures already have climbed as much as 2 degrees Celsius, or 3.6 degrees Fahrenheit, surpassing previous cycles. And chicks are taking a bigger hit. [Editor's note: Fahrenheit number corrected on 8/29/14]
Even when the current warming cycle ends, around 2030, "it's not going to be that cold at all," Hansen says. "I don't want to be alarmist. But global warming is definitely felt here.... It makes things happen fast and the birds are suffering."
He frowns as he thinks about their future. "I'm fearing it's not going to be pretty."
Just five chicks
The scene is virtually the same on Flatey Island, 200-some miles to the northwest.
"Another terrible year," says Petersen, stepping through thigh-high grass dripping with recent rain to survey an Arctic tern colony. A dozen or so of the fierce black-capped birds wheel overhead.
"Normally, there would be hundreds of birds here," the ornithologist says. Now, "there may be a few chicks. But they probably won't make it." Petersen's been coming to this island to count and band birds for 41 years. Some summers, he and his colleagues have banded 800 fat, gray Arctic tern chicks."This year," he says, "we've done five so far."
Reykjavik artist Ragnar Olafsson also notices the difference. When he came here as a child, the sky was thick with terns dive-bombing anything that came near their nests. They aimed for the head and frequently drew blood. "I was terrified! I wore two or three hats." Now he can go hatless.
The Arctic tern is another special bird to Icelanders, who see its arrival as a sign that the long, dark winter is over. The bird is revered for its astonishing migration – flying from the Arctic to the Antarctic and back every year – nearly 50,000 miles. "Everybody knows it. Everybody likes it," says Petersen. "People used to say that it always came on the fourteenth of May to the pond in the middle of Reykjavik. There used to be a colony there. But no longer."
Petersen is here with an international group of researchers looking into what's going wrong with the seabird colonies in Breidafjordur Bay. The area is a nesting nexus for a variety of species, and breeding looks dismal again this year for kittiwakes, puffins, shags and murres as well as terns.
This is at least the tenth year in a row that tern breeding has been poor, Petersen says, parting grass to look for the white streaks that are telltale signs of a nest. He finds only the five chicks, even though just a month earlier he had seen around 200 terns in this same spot getting ready to nest.
"There are hardly any chicks around," Petersen says. "The birds are just sitting on their empty nests. And eventually they will leave.
"This is what we are seeing in the whole of Flatey," he added, "and further afield."
As in the Westmans, the birds' preferred prey seems to be in short supply, and the researchers are attaching geologgers to record their foraging trips. In the evening, the group motorboats out to a small island with a lighthouse. First up for tagging is an angry fulmar, spitting a foul-smelling orange glob of stomach oil at British researchers Kane Brides and Lloyd Park. "They do that," Park says, unfazed.
Morten Frederiksen, a Danish scientist from Aarhus University who works regularly with Petersen, grows pensive. "I was on this island 20 years ago, and we were ringing [banding] kittiwakes," he says, treading carefully across the island's slick basalt pillars. "The whole island was covered with kittiwakes. ... And now there's just these few left. Everything's changed."
Olina Jonsdottir and her husband Hafsteinn Gudmundsson have lived on Flatey Island for nearly 50 years.
"Seabirds give us a window into what's going on in the sea," Frederiksen says. "These very widespread problems we're seeing for the seabirds, in Scotland, in western Norway, the Faroes and Iceland, tell us that something's changing."
Ocean heating can alter currents, bringing relatively fast and sudden weather changes over a vast area. Warmer waters also hold fewer nutrients for marine life. Plus, some scientists think that climbing water temperatures make for faster fish. "The warmer they are, the faster they can swim," the theory goes, Frederiksen said. "And some birds won't be able to keep up."
It's not just an ecological issue, it's an economic one, since fishing is such a critical part of the North Atlantic's economy. "Probably the biggest thing you notice is the fisheries," Frederiksen said. "And that affects people's livelihoods. It even affects international relations in some circumstances."
Back on Flatey, Petersen wades across another wet meadow, estimating numbers of Arctic terns. "Counting birds is tricky," he says. Some are pacing overhead. Others watch vigilantly from fenceposts. Still others lounge on rocks by the water below.
"That's what they do when they don't have any parenting duties to take care of," Petersen explains of the basking birds. The behavior is normal for August, when the chicks are grown. But not on this day in the middle of July.
No one knows exactly how many Arctic terns there are, but Iceland is believed to hold nearly one-third of the world's population, perhaps 500,000 pairs. Petersen and colleagues are conducting a census of Iceland's terns for the first time in a decade. Their findings will be part of the first-ever circumpolar Arctic tern review, coordinated by the Arctic Council's biodiversity working group.
Dire reports are already coming in from elsewhere. Petersen's longtime colleague, Sverrir Thorstensen, gets a phone call from a friend counting terns in Iceland's largest colony, Hrisey Island. Ten years ago, there were 15,000 pair in this colony off the north coast; the decade before, there were 25,000. With a grim face, Thorstensen relays the news of the latest count: "Very simple answer. All the chicks are dead."
Kittiwakes and murres nest on a cliff on Heimaey Island. Numbers are drastically reduced.Cheryl Katz
The retired biology teacher from Akureyri is the No. 2 bird-bander in Iceland. He's banded 62,000 birds in the past 35 years. When he visited the colony himself earlier in the season, things looked good: lots of nests, lots of eggs.
"All dead," he repeats now, in a low voice. "There are hundreds lying dead."
Our high-carbon lifestyle is turning up the oceans' thermostat, and seabirds are feeling the heat. Some will escape by heading north – scientists say a redistribution is already underway. But there's a cap on how far north they can go. More and more species will be trying to cram into a confined space. Sea cliffs and burrow-grounds are limited, and building nests in the open leaves them vulnerable to predators, which also are moving north.
A nasty cocktail
At the same time, civilization's toxic stew is swirling its way north, where it may also contribute to the seabirds' decline. Levels of mercury, which can damage nervous systems and interfere with reproduction, are rising in marine wildlife throughout the North Atlantic. For other chemicals, the scenario varies by location and foraging behavior. For example, while the banned pesticide DDT has declined in most areas, it remains high in glaucous gulls in Arctic Norway. Brominated flame retardants are ubiquitous, and the perfluorinated coatings called PFCs are holding steady or even increasing in northern Canada's kittiwakes, fulmars and murres. In Iceland, levels of the legacy pollutants polychlorinated biphenyls (PCBs) and other contaminants are so high in murre eggs that authorities recently warned people not to eat them.
It's difficult to tell precisely where the birds are encountering these chemicals, said Canadian researcher Provencher, who has conducted exposure studies in Arctic Canada. It's also hard to tease out what the health effects are.
While pollution is a definite concern, ecotoxicologists say levels of most contaminants they're finding in northern seabirds don't appear high enough to jeopardize health on their own. But mixed together, they can make a nasty cocktail, adding to the stress caused by food shortage and habitat change. "The combination of all these factors together could wear down the birds," Provencher said.
Mercury levels have grown so high in Arctic terns and other seabirds that they are "definitely in the range where reproduction could start to be affected," said Jennifer Provencher, Carlton University.
One important standout, however, is mercury, a poisonous metal spewed by coal-burning power plants. Mercury levels have grown so high in Arctic terns and many other seabirds that they are "definitely in the range where reproduction could start to be affected," Provencher said.
Arctic terns like this one on Flatey Island migrate from the Arctive to the Antarctic and back every year.Cheryl Katz
Tiny plastic particles in the ocean are another surfacing menace. So small that they're nearly invisible, these 5 millimeter (.19 inch) or smaller "microplastics" can be eaten by the smallest marine organisms and biomagnify up the food chain. A recent study found microplastic concentrations frozen within Arctic sea ice that were twice as high as in the notorious Pacific Gyre, and the authors warn that huge loads could dump into the ocean as the polar sheets melt.
All these threats – shrinking food supplies, habitat loss, pollution and more – are expected to magnify as melting Arctic ice brings increased shipping, fishing, mineral and oil drilling and commercial development to the region.
Yet for all the perils they face, there are still millions of seabirds in the north, Petersen says, watching the birds circling Flatey Island and paddling on the bay. "They haven't vanished yet."
Still, Jonsdottir misses the raucous sounds of the seabirds near her home there: the boisterous chatter of the kittiwakes, the piercing squall of the terns. "The birdsong has quieted down," she said. "It has died down."
Part 3 of Winged Warnings, published in conjunction with nationalgeographic.com. Check out the rest of the series here.