A freshwater marsh is a shallow area filled with reeds, cattails, sedges (plants that have their roots in water and foliage above water). The fresh water creates habitat for birds and animals.

The Red-winged Blackbird is only 7-10 inches big and has a wingspan of 12-15 inches. It eats grains, seeds, berries, wild fruit, insects, caterpillars, and snails. Red-winged Blackbirds can be found in grasslands, bushes, shrubs, thickets, marshes, swamps, freshwater, lakes, and rivers. Nests are built in reeds, tall grasses, or cattails.

The Northern Harrier is one of the top predators in the wetlands. Although this bird is only 1-1/2 feet long, its wingspan is 3-1/2 feet, which makes it a strong flier. It feeds mainly on rodents, but also eats snakes, frogs and insects. It can be found in open grasslands or marshes. Harriers are sometimes called "Marsh Hawks," because they are the most common hawk seen in marsh habitats.

The black-tailed jackrabbit is 1-1/2 to 2 feet long and has a 2 to 4 inch tail. This jackrabbit can be found near fresh water marshes and in open fields. In summer, it eats many kinds of plants like alfalfa. In winter, it depends on woody and dried vegetation. Jackrabbits are most active in late afternoon and are somewhat social, feeding in loose groups. They signal danger by thumping their hind feet.

The American Coot might look like a duck, but is actually a type of bird known as a rail. Rather than having webbed feet (like a duck), coots have lobed toes (more like a chicken). It is 1-1/4 feet long and has a wingspan of just over 2 feet. It eats leaves, seeds, and roots of aquatic plants and it can be found in marshes, shallow lakes, freshwater or alkali (salty) ponds; muddy sloughs (wetlands) with thin vegetation.

Cattails are common in marshes and along freshwater lakes and rivers. The plant has long, sword-like green leaves and sprouts a tall, green flower spike which ripens into brownish tufts of hairy seeds. It was an important source of food for the Ohlone Indians who lived around the Bay. Flour can be made from the underground root and the green flour eaten like corn on the cob. Cattails provide an important source of food and water for birds and wildlife, and it is native to California.