Lake Superior is large enough to generate its own small tide, a tidal action called seiche that influences Fish Creek. At times, water from Chequamegon Bay pushes into the creek, while at other times water from the creek flows into a more shallow lake edge. The resulting fluctuation of water levels is largely responsible for the estuary at Fish Creek. Freshwater estuaries and their associated wetlands are very rare. The estuary is a dynamic mixing zone where a number of animal and bird species depend on the habitat it provides. Wetland birds skulk around in dense vegetation, bald eagles are often found on sandbars or perched in shoreline trees, waterfowl and shore birds migrate through the area in spring and fall, marsh wrens hop from cattail to cattail singing, and great blue herons stalk shorelines in search of fish. Humans also depend on the estuary for stability and protection as well as aesthetic and recreational opportunities. Functioning like a large rain garden, it absorbs upstream runoff and prevents large-scale flood events while filtering out pollutants and sediments. People have long enjoyed the serenity of this estuary, and writer and conservationist Sigurd Olson drew inspiration for future writing while hunting here at Fish Creek. Although many roads and structures were built on and around estuaries, lakes, and wetlands before their value was fully understood, habitat restoration, stormwater management, and invasive species control can minimize the impact of past development while preserving this natural resource.