As you look out at the creek, look for the beaver lodge and dam in the water. The dam, made of grass, rocks, sticks, and mud, slows down the flow of water in a stream. In this calmer water, the beavers will build a lodge to live in, a domed structure made of sticks and mud that protects them from predators. These dams and ponds help control soil erosion and reduce flooding. They are also important habitats for other wetland animals, such as birds and fish.