"It's July on Alaska's North Slope, and scientist Denver Holt is in Utqiagvik surveying nests. Denver has been coming here since 1992, and the snowy owls he studies have been coming here much longer: thousands of years. With its mix of coastal, low-elevation tundra and a rich presence of lemmings, the North Slope is the only area in Alaska where snowy owls regularly nest. How do snowy owls decide where they will nest? How do they manage to arrive...

Vast, wild, and untouched, the Arctic National Wildlife Refuge (ANWR) is where some of the world's greatest wildlife spectacles unfold. Situated in the northeast corner of Alaska, this refuge has long protected survivors of the Ice Age that still roam a frozen wilderness.

"Rat Island rises from the icy gray waters of the Bering Sea, a mass of volcanic rock covered with tundra, midway between Alaska and Siberia. Once a remote sanctuary for enormous flocks of seabirds, the island gained a new name when shipwrecked rats colonized, savaging the nesting birds by the thousands. Now, on this and hundreds of other remote islands around the world, a massive--and massively controversial--wildlife rescue mission is under way....