The Concord Marshes lie along the southern shore of Suisun Bay at the western edge of the Sacramento River Delta. Along with Suisun Marsh to the north, they ecologically connect the wetlands of the Central Valley with those of San Francisco Bay. Extending east from the town of Martinez to near Pittsburg, the best habitat is now mainly on the north side of Waterfront Rd., extending to the edge of the Bay. The wetlands may be divided into three main areas: Martinez Regional Shoreline, which includes a large, constructed "duck pond" and tidal saltmarsh; McNabney Marsh/Pt. Edith (Department of Fish & Game), a large area of freshwater and saltmarsh on either side of the Benicia-Martinez bridge; and the Concord Naval Weapons Station, which extends this habitat to the east. The amount of tidal marsh vegetation varies greatly from year to year, which in turn affects the number and types of bird species. Access to the wetlands is limited to a few roads into the marshes, some of which require checking-in at guard posts. The Naval Weapons Station also includes about 8000 acres of grassland interspersed with riparian stringers extending inland, south of Waterfront Rd

The estuarine wetlands of San Francisco and San Pablo Bays are recognized together as a Western Hemisphere Shorebird Reserve Network (WHSRN) Site of Hemispheric Importance for shorebirds, the highest possible ranking.

Updated December 2008

The Concord marshes support thousands of waterfowl from fall through spring (5000 Greater Scaup and 8000 other ducks on the 1994 Napa Solano Christmas Bird Count), as well as high numbers of resident waders (especially American Bittern) and rails. Black Rail (at least 150 pair in 1981, fide Jill Hedgecock), California Clapper Rail (6 birds recorded in 1994, ibid), and the endemic Suisun Song Sparrow occurs here, as do thousands of migrant and wintering shorebirds when mudflats are exposed. Short-eared Owl is known to winter here, and a handful of California Least Tern have begun breeding adjacent to the Pacific Gas and Electric Plant in Pittsburg, foraging within this Important Bird Area. A pair of Peregrine Falcon has begun nesting on the Benicia Bridge, and also forages heavily in this Important Bird Area.

Help us learn more about the birds at this Important Bird Area! Enter your birding data online at Calfornia eBird! (http://ebird.org/california/)

Much of the habitat is either formally protected and managed for conservation, or protected and managed on Department of Defense property. Tranfer from the Navy and subsequent redevelopment of the upland 8000 acres of the Concord Naval Weapons Station is currently being planned, although the conservation component of this plan is not yet known. The Concord Marshes are proximal to many heavy industrial facilities such as oil refineries, which have polluting effects on the adjacent air and water. In 1988, the 100 acre McNabney Marsh suffered acutely from a 400,000 gallon oil spill leaking from an adjacent oil refinery. Exotic plants are the target of recent conservation plans.