Prairie Pothole Region

The Prairie Pothole Region covers roughly 800,000 square kilometers across the Canadian provinces of Saskatchewan, Manitoba and Alberta and the American states of Minnesota, Iowa, North Dakota, South Dakota and Montana, a landscape of shallow depressions left behind when buried blocks of glacial ice melted at the end of the Wisconsin glaciation about 10,000 years ago. The resulting potholes fill mainly from spring snowmelt and rain rather than connected streams, and the wetlands they create support more than half of North America's migratory waterfowl, including over 60 percent of the continent's breeding mallard, gadwall, blue winged teal, northern shoveler, northern pintail, redhead and canvasback ducks. More than half the region's original wetlands have been drained for agriculture.