A temperate grassland known as prairie once covered one-fifth of North America from Texas to Canada and from the Rockies to Illinois, supporting many distinct plants and animals, and the Samuel Ordway, Jr. Memorial Prairie preserves a remnant of that landscape within the Missouri Coteau, a region stretching from Alberta to Manitoba and south through the Dakotas. Formed by retreating glaciers 10,000 years ago, the area was left with glacial rubble, large boulders, and depressions that became wetlands known as prairie potholes. More than 400 wetlands on Ordway Prairie provide important breeding habitat for several thousand pairs of waterfowl, including mallard, gadwall, pintail, and shoveler, as well as shorebirds, grebes, rails, and herons, while 7,800 acres of contiguous mixed grass prairie support birds such as Baird's sparrow, burrowing owl, and Sprague's pipit. More than 300 plant species grow here, with tallgrass species in lowlands, mid-height grasses on hillsides, and short grass species on hilltops. Wildlife habitat depends on land management practices such as grazing, controlled burning, cattle and bison grazing, and prescribed fire, which echo the historic effects of wildfire and the grazing of large bison herds. The prairie also preserves signs of human history, including a teepee ring marking a temporary Native American campsite and the remains of a homestead occupied by a family of three in the early 1940s. The Nature Conservancy works with conservation organizations and private landowners to limit threats such as agricultural conversion, fragmentation, incompatible grazing practices, and invasive species, and this preserve, the Conservancy's largest in South Dakota, was acquired with funds from Katherine Ordway and named for her cousin Samuel H. Ordway, Jr., a co-founder of the Conservation Foundation and an early advocate for environmental protection.