A functioning, resilient Puget Sound ecosystem is defined to include tidally-influenced wetland habitats at the estuaries of Puget Sound’s major rivers that provide ecosystem functions, goods, and services. Approximately three-quarters of river delta tidal wetlands have been lost or degraded in Puget Sound. River delta estuaries, a unique environment where freshwater mixes with salt water and sediments collect, provide important feeding and resting habitat for young salmon, migratory birds, and many other species that cannot find these unique benefits in any other place in our landscape. These areas are also highly valuable for people: they have been heavily developed and they provide some of the most fertile agricultural lands in the region. The Estuary Vital Sign tracks protection, loss, and restoration of large and small estuaries.