The thick-billed murre is a creature of habit. Year after year, the northern seabird, which looks like a small penguin wearing a tuxedo, returns to the same spot of bare rock cliff to make its nest. Same, that is, to within half a centimetre. And a vast majority of the birds, which form massive, cacophonous colonies throughout the circumpolar Arctic, will settle within a metre of where they were born to make their nests for the first time.
This rigid devotion to ritual, and the murre’s status as a long-lived, quintessential Arctic bird that needs ice, means the seabird can serve as a reference point for the changes swirling around it in the North. In turn, this serendipitous combination of its characteristics has led to one of the longest-running zoology studies in Canada, a 39-year extravaganza of leg banding, chick counting, nest watching, and food monitoring conducted at a research station set up by the Canadian Wildlife Service, in 1984, on Coats Island. It is still in use.
Nestled near the top of Hudson Bay, in the Kivalliq region of Nunavut, Coats Island is a nearly perfect laboratory. At about 5,500 square kilometres, the rocky outcropping is big enough to have an airstrip for charter flights from Iqaluit and house the handful of cabins that make up the station’s living quarters. Better still for the study, no one lives on it. In fact, it’s the largest uninhabited island south of the Arctic Circle in the northern hemisphere.
Every spring once the ice recedes, 30,000 pairs of murres migrate to the island from the east coast of the continent for breeding season. They settle, thickly thronged in pairs, on narrow ledges of sooty Precambrian rock slung down the side of the cliffs. There, each pair tends to a single egg in an open nest, taking turns raising one chick a year.
The cliffs are relatively easy for scientists to rappel down. The nests, being both in full view and tightly packed together, are easy to monitor. Scientists sit in blue-painted plywood boxes built on the cliffs for days on end every study season, buffeted by the piercing stench of murre guano and the birds’ clamour, which brings to mind the laughter of thousands of demented crows.
After all these decades, the murres are telling scientists that wildlife patterns in the North are changing at a bewildering clip. Change is so deep and so fast that the biologists who have been tracking the birds on Coats reckon the island may eventually be so warm—so un-northern—that the murres will disappear from its cliffs.
Already, climate disruption has forced most of the murres to flee from their former stronghold of Svalbard, an archipelago in Norway. They’re dwindling in Greenland, too. “We expect that to happen at Coats Island,” says Kyle Elliott, a professor and Canada Research Chair in Arctic Ecology at McGill
University, in Montreal, and one of the authors of the long-term murre study published earlier this year in the journal Arctic Science. “And when it happens, it happens very rapidly, as shown in those other two places.”
It’s not just murres. Across the North, animals and plants are on the move. New species are creeping into places that have become welcoming, weather-wise. Old species are either dying out or moving on in search of cooler areas. From top to bottom, the Arctic food web is shifting. The North is in flux. But the North is also a prophet. Unless we can halt climate destabilization, what’s happening here tells us what’s going to happen in other parts of the world, too.
Regions across the planet’s high latitudes are changing faster than almost anywhere else in the world, a phenomenon climate scientists call polar amplification. The Arctic has heated up nearly four times faster than the global average since satellites started tracking the warming in 1979, according to a study published in 2022 in the journal Communications Earth & Environment.
That extra heat is hitting the whole system hard, especially the marine sphere. Arctic sea ice is vanishing month by month. Thick, packed sea ice that used to last for years is rarer now. Most of it forms and vanishes in the same year. What’s left of the old ice is thinner. The part of the ocean that does get cold enough to freeze is freezing later in the year and melting earlier, allowing warmer temperatures to penetrate even further north. That means the usual birds, fish, crabs, and marine mammals, including seals and polar bears, are disappearing in some regions.
The loss of sea ice triggers a chain reaction and is one reason the Arctic is so disproportionately slammed by climate disruption. Ice reflects solar radiation back into the atmosphere. But when it melts, the dark, open ocean absorbs sunlight and its heat instead, speeding up further thawing. Climate scientists call this a feedback loop: a little melting leads to more melting.
As the ocean changes, so does the land. Permafrost is thawing and the tundra, typically brown, is turning green from more plant growth. That includes shrubs, which are showing up where they never grew before. And while some people in more southerly latitudes may think of the North as barrens, it is fantastically rich with life. Climate scientists are worried that as the ice and snow recede, the ecosystems that emerge in the warmer temperatures may not be nearly as varied or abundant. This complex web of life is poised to falter, according to a 2022 United Nations’ Intergovernmental Panel on Climate Change report, and the consequences are stark: “Multiple physical, ecological and societal elements of polar regions are approaching a level of change potentially irreversible for hundreds of years, if not millennia.”
And those changes in northern waters and lands ripple across the rest of the planet. The Arctic serves as a thermostat for other parts of the globe, regulating the flow of heat and moisture. As it warms, so does the rest of the planet. It’s another feedback loop.
When the field station on Coats Island launched, in 1984, tracking climate change through the lives of its avian inhabitants wasn’t on the agenda. Its colony of murres migrates from the island to Newfoundland and Labrador for the winter. There the birds, known locally as turrs, are hunted and form an important part of that region’s food security. So, the aim of the study was mainly to count the murres and monitor population trends. Since then, scientists have spent weeks each year camping out on Coats, watching the birds while trying to avoid polar bears. The program’s officials even procured special triangle-shaped metal “murre bands” to affix to the birds’ legs. The bands allow scientists to track the lives of individual murres and have led to a treasure trove of information.
A decade or so after the study began, the scientists realized the birds, which are near the top of the Arctic food chain, also offer a superb window into changing environmental conditions in the region. Out they go to the ocean to find food on the underside of floating ice. Back they fly with a single fish in their beaks for their chick. For Elliott, it’s like having thousands of free volunteers going out to sea gathering information every day.
In the early years of the study, murres were mainly bringing back Arctic cod. The fish is such a rich nutritional source that it has traditionally been a keystone food for much other wildlife in the Arctic, including narwhals and the seals polar bears feed on. Elliott calls those larger animals “repackaged Arctic cod.”
Arctic cod like the ice and thrive only in water below 4°C. But by the mid-’90s, the ice had retreated, the water had warmed, and the murres began bringing back capelin, a smaller fish typical not of the Arctic, but of the North Atlantic. Today, capelin are the murres’ main food. They’re not as nutritious, so the chicks don’t grow as well. It means the area around Coats Island, which is at roughly the same latitude as Iceland, has transformed into a north temperate system from an Arctic system just over the past four decades. “What they realized in the ’90s was that there was actually this shift in [the murres’] diet going on, which coincided with changes in ice cover and sea-surface temperatures associated with climate change,” says Allison Patterson, a wildlife biologist now based in Prince George, B.C., who is another co-author of the long-term study paper. And that meant scientists could also see what was happening in the broader marine sphere.
Higher temperatures are leading to other changes, from both large and small creatures. Mosquitoes, a parasite of murres, have turned into a danger because they have become far more abundant earlier in the year. In the late-’90s, the combination of so many mosquitoes and higher temperatures killed off adult murres and caused some pairs to desert their eggs.
At the same time, polar bears suddenly began frequenting the island, feasting on both eggs and chicks. The bears, which in cooler eras would still be fattening up on seals, have been forced by the lack of ice to come to shore about a month earlier than they want to. “They’re driven so crazy by hunger that they’re actually venturing out onto these cliffs, venturing out to places that I would never go, and sometimes injuring themselves to feed on these murres,” Elliott says. “And you know, one polar bear can go through an awful lot of eggs. They’ll eat a third, a half of the colony.”
Not only that, but murres, so exquisitely adapted to the cold, suffer in the extra Arctic heat. In fact, Elliott says they’re the least tolerant of warmer temperatures of any species scientists have examined so far. Black-backed and sitting on a black cliff ledge, they absorb the sun’s rays. Even 22°C can push them into overheating, dehydration, reproductive failure, and death. And those days are becoming more common on Coats Island.
Some of the threats related to climate change are not as obvious. For murres to reproduce, a whole sequence of interconnected events has to occur, all programmed by their hormones. That includes when they migrate and when they breed. Their hormone system is linked to the cycle of night and day, which is changing slowly. Today, murres lay their eggs about a week earlier than they did in 1990.
But the environment that the adults and their chicks depend on for food responds to temperature, not to hours of daylight. And temperature is changing a lot and quickly. The ice breaks up a month earlier now, setting off what Patterson calls the Arctic’s “pulse of productivity.” It’s like the moment on land when trees start to bud and flowers begin poking up through the soil. In the ocean, when the ice breaks up, the phytoplankton bloom, zooplankton feed on them, the fish proliferate, and the food web kicks into high gear. The murres and their chicks used to sync perfectly with that cycle. Now, they’re late. That means they don’t get the quality of food they once did. Biologists call this a mismatch.
It’s not a recipe for success.
In 1973, about a decade before the Coats Island murre study began, another multi-decade investigation of the North’s animals and plants took off. This one was terrestrial. The federal government was setting up Kluane National Park and Reserve, which is nestled in the southwest corner of the Yukon and is now part of a UNESCO World Heritage Site. Charles Krebs, a field ecologist at the University of British Columbia, started assessing the small mammals that live in the area. Among them were red-backed voles, deer mice, lemmings, and snowshoe hares. “We went around the park and we found more species there than there are anywhere else in Canada,” says Krebs, who is now in his late 80s and still studying the animals along with a roster of colleagues and students. “It’s very strange to think of it because it’s so far north.”
This rich array of small mammals congregated in the North after the last ice age ended about 10,000 years ago and crossed to this continent from what is now Siberia. At the same time, other small mammals pushed up from the south. “And they all overlapped in Kluane,” Krebs says. “It’s kind of an interesting area.”
It matters because much of the biological activity in Kluane revolves around the small mammals, particularly snowshoe hares, which hit a population peak and then decline over the next nine or 10 years before rising again. The small creatures are food for many larger mammals and birds, much like Arctic cod are in the marine sphere.
And what happens in Kluane mirrors what is happening across the boreal forest, which makes up about two-thirds of Canada’s landscape. The life cycles of small mammals across this zone form a significant part of the biological workings of Canada as a whole. These creatures drive the food chain, providing calories for larger animals, whether directly or indirectly. Krebs says, “Mice are more important than the caribou.”
And while his study originally aimed to find out which species were in the area and track where they live, it has morphed into an examination of the effects of climate disruption in the North, just as the murre study did. Krebs and his colleagues are running to keep up because things are changing so much. “The little things are really causing a lot of the changes,” he says, “and we have less and less knowledge about them.”
Kluane is getting warmer. Winter is getting shorter. Plants are growing more, but ground berries, a key food for many species, are growing less. Shrubs, such as willow bushes, are moving in. Red-backed vole populations are skyrocketing; their density has more than doubled since 2000.
But of all the changes, one of the most stark has been the collapse of the population of Arctic ground squirrels. Rudy Boonstra, an emeritus biology professor at the University of Toronto who has collaborated with Krebs for decades, says the squirrels used to be abundant. They were a preferred summer prey of coyotes, lynx, and great-horned
owls when snowshoe hare populations were thin. In fact, they once made up 17 per cent of the biomass of herbivores in the boreal forest of southern Yukon during the summer. In 2000, the squirrels vanished across much of that part of the North. They have not returned.
Boonstra has two theories about what’s happened. The first is that squirrels can’t digest the shrubs showing up in the warmer climate and pushing out the plants they used to digest easily: forbs, the low-growing plants that flower for brief periods in the Arctic. Squirrels have simple digestive systems, incapable of processing the cellulose and other tough fibres found in shrubs. That’s a particular problem for young squirrels, which have to pack on weight in just seven critical weeks between weaning and hibernation.
Or it may be the height of these new shrubs. The squirrels, which live in colonies, need to clap eyes on their predators to know they’re in danger. At that point, the squirrels call out an alarm to alert the whole colony to dive into their burrows for safety. That works when they can see their predators. But now, it’s so warm that willow bushes have taken over, obscuring lines of sight. “They’re sitting ducks,” Boonstra says. “They cannot see the predators coming—they’re dead.”
Patterson still has fond memories of her five research stints on Coats Island. She would sit on the cliffs, shielded from the birds behind plywood blinds, and simply watch them, day after day, revelling in the commotion, learning their quirks, and tracking the most intimate details of their lives. The murres hardly noticed the humans. “One of the things that I love about just doing research in the Arctic,” she says, “is that, more than other places, I get that sense of how nature goes on around us, and we’re just this small part of it.”
Except, of course, as Patterson and the other scientists have chronicled, humans are altering almost every aspect of Arctic life through our collective actions. And it’s only through the painstaking knowledge these scientists and others have amassed over so many decades that we can figure out how to stop the collapse from spreading even further.
But what if we ignore the prophesy of the murres and opt not to retreat from further ruin? Then, hope lies in the resilience of life itself. Just as plants and animals came back in new configurations after the paroxysms of the last Ice Age,
