Sandwiched between Becharof National Wildlife Refuge to the north and Izembek NWR to the south, Alaska Peninsula National Wildlife Refuge presents a breathtakingly dramatic landscape made up of active volcanoes, towering mountain peaks, rolling tundra and rugged, wave-battered coastlines. As is the case with most of Alaska's coastal refuges, salmon provide the principal "nutrient engine" for Alaska Peninsula, supporting the species that prey upon them and enriching the rivers and surrounding lands after they spawn and die. Where there are salmon, there will usually be bears, and when the fish are running, Ugashik Lakes and the streams that surround them attract brown bears in great numbers. (Black bear are not found on Alaska Peninsula National Wildlife Refuge.) Other large land mammals include wolverine, the caribou of the approximately 7,000-animal Northern Alaska Peninsula Herd, wolves and moose. The latter are relative newcomers, first observed on the peninsula in the early 1900s, and uncommon until the 1950s. The refuge's coastal and offshore waters are home to sea otters, harbor seals, sea lions and migrating whales. Alaska Peninsula's numerous wetlands and often rugged shoreline provide habitat for migratory birds, including ducks, geese and shorebirds. The refuge is also home to the westernmost black cottonwood forests in America, which offer both migration stop-over and nesting habitat to neotropical land birds.