A rich, rolling wilderness that stretches along the Arctic coastline is the permanent home of grizzly bears, wolves, foxes and polar bears, and the seasonal home to migratory birds and barren-ground caribou. Each spring, the North Slope bursts to life as millions of swans, geese, cranes, shorebirds and ducks descend to the plains to nest and feed.

The North Slope is also the birthplace of the Porcupine caribou, an internationally significant herd of more than 120,000 barren-ground caribou. Each year the herd migrates from boreal wintering areas in central Yukon to the calving grounds in Alaska's Arctic National Wildlife Refuge and the Yukon's Ivvavik National Park.

The herd is the anchor of this fragile northern ecosystem, sustaining carnivores like wolves, bears and wolverines-species that shape the landscape and affect animals further down the food chain. Harvesting from the Porcupine herd continues to be integral to the cultural survival of the Gwich'in people.

In late May, the Porcupine caribou herd completes one of the longest land migrations in the world, arriving at the coastal plains where calves are born and the cycle of life in the north is renewed.