At the southeastern tip of Scout Island, exposure to wind and waves has washed soil away from the roots of trees and shrubs, and the eroded soil settles to the bottom of the lake, eventually filling it in. The same thing happens when dirt from nearby fields blows or washes into a lake. Over time, prairie lakes become filled with silt and return to a prairie grass stage, and the natural succession from lake to pond, pond to marsh, and marsh to prairie is greatly affected by man's land use practices. In the meadow to the north, common milkweed has smooth stems and leaves, and clusters of pinkish flowers develop into bird-shaped seedpods packed with downy seeds. Indians ate the young seedpods, and the whitish milk that oozes from a broken stem or leaf has been used for chewing gum, a cure for warts, and treatment for ringworm.