Swarm of butterflies migrates through Oregon

PORTLAND, Ore. — A man captured mesmerizing video of a rare event in Oregon.

Steve Andrijiw captured video of countless butterflies migrating through the Pacific Northwest in August.

Andrijiw identified the swirling butterflies as California Tortoiseshells.

“This event happens every 5-6 years. The Spruce Lake fires shrouded the view of Crater Lake but Mother Nature treated us to an amazing show,” Andrijiw wrote.

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The species are known for having population explosions that cause the butterflies to migrate to new areas.

“Breeding localities in summer vary widely from year to year — sometimes in the high southern Sierra, sometimes in the Cascades … sometimes only in far northeastern California or even farther north,” the University of California Davis website states.