LearnBoost welcomes Heron
Before the arrival of European settlers in the nineteenth century, much of the Sacramento valley was taken up by seasonal wetlands and grasslands. By the beginning of the twentieth century much of this had been replaced by farmland, particularly for the growing of rice, and the rivers no longer create new wetlands because their flow is controlled by levees and irrigation schemes. Less than 10% of the original wetland area remains. Migrating birds have continued to use the area, and resting in the rice fields, consumed considerable quantities of the crop.
In 1937 the United States Fish and Wildlife Service, with the aid of the Civilian Conservation Corps, began the process of creating a refuge within dry, alkaline lands between the towns of Willows and Maxwell. This was the original Sacramento NWR. From the 1940s onward, additional refuges were created, so that the Sacramento NWR Complex now includes the following refuges, located between 80 and 145 kilometres (50 and 90 mi) north of the city of Sacramento:
The total area of the refuges is about 140 square kilometres (35,000 acres)s).
The water flows in the refuge have to be controlled artificially, and the vegetation has to be managed actively through irrigation and burning, to ensure that the wetlands remain productive, and provide adequate food and resting places for the birds. Between them, the refuges provide a range of habitats: seasonal marshes, uplands, permanent ponds, and riparian areas.
The refuges are provided with facilities for visitors, though these have to be limited to avoid conflict with their primary purpose of conservation. The layout of the wetlands has been planned to allow visitors a good view of the birds while minimising the risk of disturbance to them. There is a visitor's center at the Sacramento NWR, and routes for car tours on the Sacramento and Colusa sites, though visitors are allowed to leave their cars only at selected sites. There are walking trails at both those sites and also at the Sacramento River site. Limited hunting is permitted on some of the sites.
Over 300 species of birds and mammals use the refuges, not all of them migratory. Among those most likely to be seen by visitors (depending on season) are:
The Sacramento National Wildlife Refuge Complex boasts a diverse flora, even though large amounts of the historic wetland has been destroyed. Among the diverse wildflowers present is the Yellow Mariposa Lily, Calochortus luteus.
Doheny · Doheny · Duxbury Reef · Edward F. Ricketts · Elkhorn Slough · Elkhorn Slough · Encinitas · Estero de Limantour · Fagan Marsh · Farallon Islands · Farnsworth Bank · Fort Ross · Gerstle Cove · Goleta Slough · Greyhound Rock · Gull Island · Harris Point · Heisler Park · Hopkins · Irvine Coast · James V. Fitzgerald · Judith Rock · Julia Pfeiffer Burns · La Jolla · Laguna Beach · Lovers Cove (Catalina Island) · Lovers Point · MacKerricher · Manchester and Arena Rock · Marin Islands · Mia J. Tegner · Moro Cojo Slough · Morro Bay · Morro Bay · Morro Beach · Natural Bridges · Niguel · Pacific Grove Marine Gardens · Painted Cave · Peytonia Slough · Piedras Blancas · Piedras Blancas · Pismo · Pismo-Oceano Beach · Point Buchon · Point Buchon · Point Cabrillo · Point Fermin · Point Lobos · Point Reyes Headlands · Point Sur · Point Sur · Portuguese Ledge ·
Heritage registers: World Heritage Sites · World Network of Biosphere Reserves · National Register of Historic Places · National Historic Landmarks · National Natural Landmarks · California Historical Landmarks · California Points of Historical Interest · California Register of Historical Resources