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.

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.