The broadcast comes from the southwest shore of Lake Superior and the Michelle Wheeler memorial wetland, a restoration project within the Flag River estuary and the Port Wing Boreal Forest State Natural Area.The wetland is one of several coastal wetlands that characterize the south (Wisconsin) shore of the lake, and provide important habitat for a wide variety of wildlife. The dawn chorus soundscape includes migrating and resident waterfowl, sandhill cranes, eagles and gulls. The nearby town of Port Wing is a recreational and commercial fishing hub, thus we can also expect to hear sounds associated with human activity as fishermen begin their day on the  world’s largest freshwater lake. 
Site information : https://portwing.gov/wp-content/uploads/2021/01/Port-Wing-Fact-Sheet.pdf