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Sacramento NWR Complex Habitats


The Sacramento NWR Complex contains critically important habitats for a great diversity of wildlife, particularly migratory birds of the Pacific Flyway. Approximately 95% of the historic wetlands, riparian areas, and grasslands in the Central Valley have been destroyed or modified. The Complex maintains nearly 70,000 acres of wetland, upland and riparian habitats.

  • Seasonal Marsh

    This is one of the most abundant habitats. It provides more food for wildlife during fall and winter than any other habitat. These marshes usually contain water from August to April and are dry in the summer months. See producing plants grow on the moist pond bottoms in the spring. When the areas are flooded in the fall, this food becomes available to waterfowl and these areas are used for resting and feeding throughout the winter months. Common plants include cattail, roundstem bulrush, alkali bulrush, swamp timothy, and smartweed.

  • Watergrass Areas

    Another type of seasonally flooded marsh where water is removed by early May. During the summer, they receive an irrigation to bring the watergrass (millet) to maturity. Floodup begins as early as August. These areas provide an important food source during the early fall and winter. Smartweed, sprangletop, spikerush, Bermuda grass, and joint grass are usually mixed in with watergrass and are also used by wildlife

  • Permanent Ponds

    This year-round water source is valuable to resident wildlife especially during the summer when most of the seasonal marshes are dry. In the spring, ducks and geese congregate here before their long migration to the northern nesting grounds. During the summer, when flooded habitat is scarce, these ponds provide nesting areas for resident waterfowl and other wildlife. During the fall and winter, they become important resting and feeding areas. Characteristic plants include cattail, roundstem bulrush, and sago pondweed.

  • Riparian Areas

    These areas found along rivers, creeks, and waterways and can be thick with plants, trees, and hiding places. This scarce waterside habitat supports the greatest diversity of wildlife. This habitat is used by small migratory bird species which include the yellow-billed cuckoo, black-headed grosbeak and spotted towhee. Cottonwoods, valley oaks, sycamores, willows, box elders, elderberry, and wild rose are common plants along the rivers, creeks, and waterways offering fish and aquatic animals cooling shade.

  • Uplands/Grasslands

    This area becomes a carpet of green sprouts after the seasonal rains. They are often restored native plants adapted to the less alkali soils. They provide nesting habitat for ducks, pheasants, meadowlarks, burrowing owls, bitterns, and northern harriers. In the winter and spring, annual grasses provide food for geese, coots, and wigeon. They also support significant numbers of insects, rodents, and reptiles which in turn are important forage items for raptors and birds. Many of the non-native grasses are invasive and pose a threat to alkali meadow vegetation. Specific habitats within the uplands and grasslands include vernal pools and alkali meadows. In early spring, vernal pools teem with aquatic creatures. Goldfields, downingia, and popcorn flowers bloom brilliantly after these pools evaporate in late spring. Other plants include: saltgrass, saltbush, and annual grasses.

  • Habitat Maps

    In late spring of each year, a Habitat Management Plan is written for each Refuge. To see the most recent Habitat Management Maps, click on the links below:

    - Sacramento NWR Habitat Map 
    - Delevan NWR Habitat Map 
    - Colusa NWR Habitat Map 
    - Sutter NWR Habitat Map 
    - Sacramento River NWR Habitat Maps (large file)
    - North Central Valley WMA - Llano Seco Unit Habitat Map 
    - Butte Sink WMA - Butte Sink Unit Habitat Map

Last Updated: Sep 01, 2015
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