As tensions between the US and Canada rise, a tiny puffin-filled island has become emblematic of a larger conflict about where one nation ends and another begins.

On Christmas morning, Anthony Ross woke up on an island at the point where the Gulf of Maine meets the Bay of Fundy. Outside, the wind whipped across the frozen brown grass, blowing snow in drifts against the lighthouse while waves lapped the rocky shore. In the next room, his older brother Russell was already awake and keeping a watchful eye on the sea.

It was not exactly how one pictures a family holiday, but for the lighthouse keepers of Machias Seal Island, it would have to make do. Once the helicopter lands on this 18-acre hunk of rock between the US and Canada, there is no going home until the end of the month.

“You are away from home for 28 days at a time; that is the hardest part. But you get used to that,” said Russell, who has been a lighthouse keeper for about 20 years.

Luckily, Russell and Anthony came prepared with turkey, presents and beer – all anyone needs for a nice Christmas day. After decorating the tree and calling their families back home in Nova Scotia, the brothers tucked into a roast dinner.

“It was a pretty good Christmas, all around,” Russell recalled.

Located smack-dab between the Canadian province of New Brunswick and the US state of Maine, Machias Seal Island is the last contested land territory between Canada and the US – but that may soon change.

In recent weeks US President Donald Trump has called the US-Canada border an "artificially drawn line" and even threatened to annex the entire nation. And as Trump's proposed tariffs on Canada have sent economic shockwaves through North America, this unassuming 20-acre island has become somewhat emblematic of the rising tensions between the neighbours and longtime allies.

The story of the dispute goes back more than 200 years. During the War of 1812, Great Britain (now Canada) and the US each laid claim to the land and the waters that surrounded it. Although the island is far too small and remote to be permanently settled, it was strategically located in the middle of a valuable shipping route, near Grand Manan Island, and neither country wanted to give it away.

In 1832, Britain built a lighthouse on the island to physically stake its claim. Since then, Canadians have been living there, helping keep sailors away from its rocky coastline and protecting the land from both human and natural foes.

That is where Russell and Anthony come in. As lighthouse keepers on the island, they are part of a long line of watchmen manning Canada’s frontier in the Atlantic Ocean. While most of the lighthouses in Atlantic Canada have closed, the government has kept this one open – in part to keep its claim on the rock.

“The opportunity we have to be here, to stay on here and man the island, it is important,” Anthony said. “There are not many light-keepers left.”

Neither brother works full-time – union........

© BBC