Jim Brandenburg / Western Grebe (Aechmophorus occidentalis) nest with egg floating in prairie pothole, Aberdeen, South Dakota

Jim Brandenburg / Farmlands encroaching on prairie potholes, North Dakota

Jim Brandenburg / Black Tern (Chlidonias niger) flying over prairie slough, North Dakota

Michael & Patricia Fogden / Spitzkoppe granite outcrop in southern Damaraland with ephemeral pool after good rain, Namib Desert, Namibia

Tim Fitzharris / Water pothole at Panorama Point, Capitol Reef National Park, Utah

Jim Brandenburg / Anvil shaped cloud over prairie pothole, North Dakota

Jim Brandenburg / Prairie potholes, a unique area where shallow depressions resulting from the scouring of glaciation create important waterfowl nesting habitat, Ordway Prairie, South Dakota

Jim Brandenburg / Prairie potholes and the critical waterfowl nesting habitat they provide, damaged by freshly ploughed agricultural fields, South Dakota

Jim Brandenburg / Aerial view of prairie pothole region, a unique area where shallow depressions created by the scouring action of glaciation creates wetland habitat, South Dakota

Jim Brandenburg / Aerial view of prairie pothole region, a unique area where shallow depressions created by the scouring action of glaciation creates wetland habitat, South Dakota

Jim Brandenburg / Farmlands encroaching on prairie potholes, North Dakota

Jim Brandenburg / Farmlands encroaching on prairie potholes, South Dakota

Doug Wechsler / Pied billed grebe in breeding plumage {Podilymbus podiceps} Lostwood NWR prairie pothole, North Dakota, USA

Jim Brandenburg / Duck (Anas sp) group silhouetted at sunset in prairie pothole, North America

Jim Brandenburg / Duck (Anas sp) in prairie slough, North Dakota

Jim Brandenburg / Aerial view of prairie pothole region, a unique area where shallow depressions created by the scouring action of glaciation creates wetland habitat, South Dakota

Jim Brandenburg / Sunset over prairie potholes, South Dakota

Jim Brandenburg / Prairie pothole, Ordway, South Dakota