Bird enthusiasts across North America are flocking to catch a glimpse of the snowy owl.  

The birds migrate from the Arctic tundra every few years. But now people are seeing them in places they have never been seen before such as British Columbia and Texas. 

Denver Holt of the Owl Research Institute says it's the biggest irruptive migration he's seen in his lifetime.  

Yellowknife wildlife biologist Suzanne Carriere says snowy owls feed on lemmings, but lemming populations fluctuate cyclically.

When the lemming population crashes, that means owls have to fly further to find food.

"They have to have good compelling reason to go all way there and if they are not finding enough food further north, than they are going south," she said.