Where: At the southern end of San Francisco Bay, 45 miles from the city.

Habitat: Its roughly 30,000 acres make this the nation's largest urban national wildlife refuge. It includes extensive areas of salt ponds, marshes, uplands, seasonal wetlands, and tidal mudflats, as well as open water.

Wildlife: Endangered species such as the California clapper rail and the salt marsh harvest mouse owe their survival in part to the support of the congressman for whom the refuge is named. Other birds include the American avocet and the black-necked stilt.

Activities: Birdwatching, hiking, canoeing and kayaking, fishing.

Contact: 510-792-0222;
http://desfbay.fws.gov/