Millions of red admiral butterflies and their cousins have invaded central and eastern Canada, filling gardens with their fiery orange and black wings.
Nobody knows for sure why the record migration from the Carolinas, Texas and Florida is underway, other than it may have been the warm winter and spring across parts of North America.
"The numbers are unprecedented and we've just never seen anything like it," butterfly distribution expert Max Larrivee told CTV's Canada AM Thursday.
Not only are the butterflies coming north in record numbers, they're also about a month early, he said.
Some estimates have put the number of migrating butterflies at around 300 million, with at least 85 per cent of them being red admirals, Larrivee said from Ottawa.
Painted ladies are also migrating north, he said.
"What we're learning is these things can migrate extremely fast over extremely long distances in very large numbers," Larrivee said.
Red admirals can travel up to 100 kilometres per day, catching wind currents and zooming along high above the ground.
The butterflies migrate to northern breeding grounds and gather food along the way, extracting nectar from flowering trees and plants, even the common dandelion.
Larrivee said he doesn't think the record migration - at least 10 times the normal number of butterflies - is an ominous sign of a changing environment.
"I don't think we need to be worried, it is just fascinating, one of the consequences of a potential global warming," he said.
Some experts have predicted the frequency and size of the mass migrations will increase, Larrivee said.
"Where it could be an issue is some of these species, especially in the case of moths, could become pests," he said.
His counterparts in the United States used social media and email to let butterfly experts up north know that the mass migration of winged insects was on its way.
