All of the higher areas are the remnants of ancient peaks, worn down over millions of years by erosion and glaciers. The Keweenaw Peninsula is the northernmost part of the peninsula (not counting Isle Royale, which is politically part of the UP). It projects into Lake Superior and was the site of the first copper boom in the United States, part of a larger region of the peninsula called the Copper Country. Copper Island is its northernmost section. Its lowest elevation is along the shoreline of Lake Huron and Lake Michigan, averaging above sea level. Its highest elevation is Mount Arvon, at . About one-third of the peninsula is government-owned recreational forest land today, including the Ottawa National Forest and Hiawatha National Forest. Although heavily logged in the 19th century, the majority of the land was forested with mature trees by the 1970s. Wildlife The Upper Peninsula contains a large variety of wildlife. Some of the mammals found in the UP include shrews, moles, mice, white-tailed deer, moose, black bears, cougar, gray and red foxes, wolves, river otters, martens, fishers, muskrats, bobcats, coyotes, snowshoe hares, cotton-tail rabbits, porcupines, chipmunks, squirrels, raccoons, opossum and bats. There is a large variety of birds, including hawks, osprey, owls, gulls, hummingbirds, chickadees, robins (the state bird), woodpeckers, warblers, and bald eagles. In terms of reptiles and amphibians, the UP has common garter snakes, red bellied snakes, pine snakes, northern water snakes, brown snakes, eastern garter snakes, eastern fox snakes, eastern ribbon back snakes, green snakes, northern ringneck snakes, eastern milk snakes (Mackinac and Marquette counties) and eastern hognose snakes (Menominee County only), plus snapping turtles, wood turtles, and painted turtles (the state reptile), green frogs, bullfrogs, northern leopard frogs, and salamanders. Lakes and rivers contain many fish such as walleye, muskie, northern pike, trout, salmon, bullhead catfish, and bass. Invasive species like the alewife and sea lamprey can be found in the Great Lakes. The UP also contains many shellfish, such as clams, aquatic snails, and crayfish. The American Bird Conservancy and the National Audubon Society have designated several locations as internationally Important Bird Areas. After being nearly extirpated from the conterminous United States, gray wolves survived in the remote northeastern corner of Minnesota and Ontario. The repopulation of wolves in this region has occurred naturally as they have expanded their territory. There is significant discussion and studies over the presence of eastern cougars