Merced Refuge, located in California's northern San Joaquin Valley, is critically important to wintering waterfowl, and attracts large concentrations of ducks, geese, and lesser sandhill cranes.

Over 2,000 acres of seasonal and semi-permanent wetlands are extensively managed to produce natural waterfowl food plants such as wild millet and swamp timothy. Thousands of ducks (primarily pintails), green-winged teal, and an impressive variety of shorebirds and wading birds, use the wetland habitat.

The refuge hosts up to 15,000 lesser sandhill cranes, the largest population in the Central Valley. Peak populations occur during November. A mixture of up to 100,000 geese (Ross', snow, white-fronted, and cackling Canada geese) use refuge marsh and croplands during November to March.