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Curious Coats Island

Curious Coats Island

With three glaring absences—human settlements, snow geese and lemmings—this giant island is an oddity of the Arctic.
By Émile Brisson-Curadeau
Nov 05
From the October/November 2018 Issue

Canada’s Arctic is so immense that few people have ever heard of Coats Island. Called Akpatordjuark in Inuktitut, it is rich in wildlife and history. Situated in northern Hudson Bay, this 130-kilometre-long landmass is one of the largest uninhabited islands in the world. The lack of permanent settlements may be explained by the fact that Coats Island is far from the mainland—more than 60 kilometres of sea separates it from the nearest island and 120 kilometres from the nearest community. But it has not always been exempt from human influence.

The island was home to the Sadlermiut. Isolated from Inuit living on the mainland, the Sadlermiut preserved different traditions and spoke a different language dialect. Their contact with whalers and other westerners unfortunately brought them diseases for which they lacked immune defenses, and by the late 19th century only a handful of Sadlermiut were still alive. Akpatordjuark is believed to be their last home before they disappeared. Ruins of their habitations, in the form of rock circles, are the only evidence of their occupancy of the island.

After the Sadlermiut, the Hudson’s Bay Company established a trading post on the island in the 1920s, targeting caribou and Arctic fox furs in particular. But the post was shut down in 1924 shortly after it was established. Some Inuit who had moved to the island nonetheless remained there long after the post was gone. “We were mainly staying on the island because it was a good place for hunting—especially for seals,” says Josiah Nakoolak, who now resides in Coral Harbour. In the late 20th century, the last family left Coats Island and it has remained uninhabited since. Nakoolak, one of the last residents, was only sixteen when he moved away from Coats Island for good, although he returns every summer to guide scientists.

A thick-billed murre (akpa) with a mouthful of capelin—a warm-water fish quickly replacing Arctic cod as akpa’s main dietary staple.


And there are many good reasons why scientists are drawn to the island. One peculiar feature is its absence of snow geese colonies. Although the birds do breed there intermittently, there is currently no known nesting colony on Coats Island—and scientists aren’t sure why that is. Elsewhere in the Arctic, huge colonies of the ravenous geese graze heavily on grasses and sedges around their nesting areas, leaving little else for other bird species. Scott Flemming, a graduate student researching shorebirds on Coats Island, says the lack of nesting snow geese on parts of the island make it an attractive destination for migratory birds and an ideal habitat for a wide range of shorebirds.


The island is also without another common Arctic resident: the lemming. Although there’s no shortage of suitable habitat for the rodent, Coats Island’s remoteness makes it difficult for lemmings to get there. Lemmings don’t hibernate in the winter, but the island is simply too far away for them to scurry over the ice. And the pack ice on Evans and Fisher straits, which surround the island, is mobile and unpredictable throughout much of the winter.

Commonly found in the Arctic, lemmings sit near the base of the food chain and provide sustenance for various types of predators, from larger mammals to birds. Some predators like snowy owls, hawks, or ermines have difficul A colony of thick-billed murre on a Coats Island cliff.ty surviving on Coats Island with its lack of lemmings. And the absence of snow geese is another factor that explains the low number of island predators. “This is likely because goose colonies can attract generalist predators such as jaegers and Arctic foxes,” says Flemming. (This has been raised as a possible explanation for the low number of fox furs traded at the HBC post, which no doubt affected its viability.)

Despite being relatively flat, Coats Island has remarkable cliffs that reach as high as 120 metres on the north coast and often plunge right into the sea. This is the perfect place for seabirds like the thick-billed murre (or akpa) to take up residence. (The abundance of this species gives the island its Inuktitut name, Akpatordjuark.) These birds gather during spring to breed in impressive colonies of tens of thousands. Leaving the cliffs only to feed in the coastal waters rich in fish and invertebrates, akpa are the most populous bird on the island. At one time, their eggs represented a good source of food for human inhabitants of Coats Island, but now only polar bears and gulls raid their nests. (The island is not completely devoid of top predators. Large mammals like polar bears hunt the plentiful marine fauna.) The glaucous gull, nesting among the akpa, is the akpa’s main enemy—it will steal eggs and chicks throughout the breeding season.

Coats Island attracts more than 90 species of bird. This includes common Arctic species like the snow bunting, but also rare birds well outside their normal range, like the great blue heron, which typically never goes further north than the boreal forest. 

This diversity is mainly due to the island’s mix of tundra habitats—coastal wetlands, rich in lakes, that support water birds like loons, and very productive meadows that provide nesting habitat to shorebirds and passerines.

The impressive cliffs of Coats Island.

The island is also a sanctuary for lost bird migrants from the south, who have missed their breeding grounds by mistake. They have to fly a long way across Hudson Bay before finding a safe place to land, so the island is a welcomed refuge for exhausted birds. Since these lost migrants are scattered and unpredictable, they aren’t the focus of study, but the bird-loving scientists who spend their summers on the island appreciate them.

The unique features of Coats Island have made it an interesting place for research because scientists can study various species of animal and tundra vegetation without the influence of common Arctic grazers (lemmings and snow geese) that have major effects on the food chain.

“The population of akpa is simply ideal for research and we have learned so much about their diet, their behavior, and their reproduction thanks to Coats,” says Kyle Elliott, a seabird biologist who has studied Coats Island akpa for 14 years. One of his future plans is to study how the diet of akpa will change with global warming. Already, the seabird team on Coats Island has noticed that capelin, a warm-water species of fish coming from the south, has become their main prey, replacing cold-water species like the Arctic cod. The island provides the ideal conditions to observe how birds and animals are adapting to these new conditions.

Larger mammals are the subjects of study too. The effects of climate change on polar bear diets have been looked at, for instance. Polar bears don’t typically attack birds, but they’ve been seen on the island’s cliffs supplementing their diet with akpa during warmer springs. And when they do, they go all out. One bear can feed on eggs and chicks from more than one hundred akpa nests in a single meal.

Uninhabited surely doesn’t mean lifeless. Hunters from the mainland still head out to the island. And with the ongoing research occurring there, curious Coats Island still has a lot to teach us.