Prior to the Gold Rush, an estimated 4 to 5 million acres of wetlands were present in California. Now, more than 95 percent of the historic wetlands and more than 90 percent of the riparian corridors have been destroyed or grossly modified.
In some years, 60 percent of the entire Pacific Flyway and up to 20 percent of North America's waterfowl population winters or migrates throughout California. Nowhere else in the world do so many waterfowl winter on such a small wetland base. Ducks Unlimited has recognized the combined Central Valley and San Francisco Bay area as one of five highest habitat priorities in North America.
California also has other regions that are important to waterfowl. Northeast California's Great Basin habitats stage massive flocks of snow geese and pintails during their spring migration. The Sonoran Desert's Salton Sea and lower Colorado River region winters large numbers of waterfowl and play an important role in supporting Pacific Flyway ducks and geese.
To date, Ducks Unlimited has implemented more than 1,300 conservation projects conserving more than 719,000 acres of wetlands and associated uplands in California alone.