Elkhorn Slough is one of the relatively few undisturbed coastal wetlands remaining in California. The main channel of the slough, which winds inland nearly seven miles, is flanked by a broad salt marsh second in size only to San Francisco Bay. More than 400 species of invertebrates, 80 species of fish and 200 species of birds have been identified in Elkhorn Slough. The channels and tidal creeks of the slough are nurseries for many species of fish. Additionally, the slough is on the Pacific flyway, providing an important feeding and resting ground for many kinds of migrating waterfowl and shorebirds.