MADISON, Wis. (AP) -- Bird watchers in Wisconsin are seeing a rare sight -- snowy owls flying south in search of food.

Hundreds of snowy owls are making their way into Wisconsin and other Upper Midwestern states from their normal wintering grounds on the Arctic tundra. The movements happen every few years and are often driven by a drop in the number of lemmings, the owl's main food source.

Ornithologist Bill Mueller tells the Wisconsin State Journal as many as 100 snowy owls have been reported already across Wisconsin. Normally no more than a dozen are spotted during a winter.

Mueller says if the state has a normal winter, the owls could stick around until early March.

The last time the owls appeared this far south in such large numbers was in 2006.