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Colourful butterflies make mass migration to the Yukon

A swarm of regal butterflies is invading the Yukon. The red admiral, with its dark wings, bright-orange bands and white spots, has been sighted throughout the territory this summer.

By Vivian Belik

A swarm of regal butterflies is invading the Yukon. The red admiral, with its dark wings, bright-orange bands and white spots, has been sighted throughout the territory this summer.

It’s a big event, says biologist Crispin Guppy, author of Butterflies of British Columbia.

They’ve only been spotted in the Yukon twice before - once in 1969 and then again in the 1970s.

To get here, the red admirals travelled thousands of kilometres from the eastern coast of the United States, through Ontario, north to James Bay and across the northern prairies.

Why they decided to go so far north and west is a mystery, says Guppy. Red admirals have small migrations most years, but huge migrations are rare. After they swarmed Russia in 1881, the same year Tsar Alexander II of Russia was assassinated, they picked up the nickname ‘the butterfly of doom.’ Since then, there have been several more mass migrations.

A few weeks ago, Guppy counted 10 red admirals flitting through his backyard in Whitehorse each hour. In Skagway, he saw about 30 every hour. The butterflies have been spotted in Carmacks, Dawson, Tombstone Park, and all over central and coastal Alaska. Males are circling the summits of Grey Mountain, Mt. McIntyre, and Golden Horn, among other peaks, waiting for females to find them.

There’s a good chance the red admirals will breed here this summer, producing a second wave of butterflies in mid-August, says Guppy.

If you see a patch of stinging nettle with a few drooping, rolled leaves, chances are you’ve stumbled upon a birthing ground for red admiral butterflies. The caterpillars, or larvae, feed on these prickly plants in the summer, using silk to wrap themselves inside the leaves. The stinging nettle protects them from pecking birds that may try to eat them. It takes a close look to spot the red admiral eggs, or to see the tiny caterpillars crawling along the prickly plant. But as the caterpillars grow over the next few weeks, they’ll become larger and the drooping, rolled nettle leaves will become more recognizable.

Guppy has already spotted signs of these butterflies-to-be in Skagway and near McIntyre Creek. But even if they do reproduce again this summer, the chances of the red admiral surviving the Yukon’s harsh winter is extremely unlikely.

“They have to hibernate as adult butterflies and they just wouldn’t be able to handle the cold,” says Guppy. “It’s not likely they’ll ever be resident in the Yukon because they don’t successfully spend the winter anywhere in Canada, except maybe around Vancouver.”

Butterflies usually found only in the south have made their way to the Yukon on other occasions. The Compton tortoiseshell, with its reddish, caramel-coloured wings, was rarely sighted in the Yukon and Alaska up until six or seven years ago. But warmer winters have kept the butterfly up north, and it now seems to be resident here. Climate change could be the reason why the Compton tortoiseshell and the red admiral have both migrated north, says Guppy.

It was the unusually warm weather throughout eastern Canada this year that allowed the red admirals to explode and move northwards. Estimates in May pegged the red admiral population in eastern Canada at a staggering 300 million strong. The west coast of North America, on the other hand, with its wet, cool weather, hasn’t had any visits from the red admirals, making their trip to the Yukon even more mysterious.

It’s still relatively unknown how climate change is affecting butterfly populations, says Guppy.

“What we don’t know, ultimately, is whether climate change will benefit them, harm them or both.”

While most of North America has witnessed an overall decline in the health and number of butterflies in the last two decades, the Yukon’s butterfly population has remained relatively stable. “In general, Yukon butterflies are extremely healthy. We’re a mecca for butterfly observers,” says Guppy.

Visitors from as far away as Russia and Japan travel to the Yukon to spot these winged insects. Our many roads leading into alpine and arctic areas flush with butterflies make the Yukon an attractive place to visit. It also helps that the Yukon hasn’t experienced the same level of habitat destruction as many other parts of North America.

Whether the red admiral will reappear in the Yukon next summer is anyone’s guess. In the meantime, Yukoners should keep their eyes peeled for any flashes of orange, white and black they may see flying past them.

This column is co-ordinated by the Yukon Research Centre at Yukon College with major financial support from Environment Yukon and Yukon College. The articles are archived at

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