Bird legs and feet are adapted to reach the niche where they feed most effectively. Many wading birds such as sandpipers, curlews and willets follow the changing tide line and probe into the mud with their beaks. Herons and egrets use their keen eyesight to locate prey and grab it with their strong forceps-like bills. Swimming birds like grebes, loons and ducks dive after fish or dabble along the bottom straining small plants and animals with their sieve-like beaks. Salt marshes and mudflat communities are nourished daily by the tides and seasonally by nutrients from freshwater runoff.
Wetlands are nurseries of the sea providing a protective nutrient-rich habitat for baby fish.
Many outer coast and offshore fish populations are dependent upon estuaries as breeding or nursery grounds for their young. More than half of local commercial and sportsfish species spend some time in a mudflat or other wetland habitat. In addition, wetlands trap sediment nutrients and pollution as well as absorb excess rainwater that flows toward the ocean from rivers and storm drains. Few of these critical areas remain in southern California. Wetlands worldwide have been transformed into housing, farmland, factories, marinas and harbors through landfill and dredging, thus eliminating the critical ecological roles of these areas.