Brandt's cormorant nesting on Alcatraz
The precipitous cliffs and offshore rocks that flank the park are a haven for colonial seabirds. Bird Island off of Rodeo Lagoon is one of the largest roosting sites in northern California for the endangered brown pelican, with several hundred making a splash in Rodeo Lagoon each Fall. Brandt’s cormorants nest at Lobos Rocks and Seal Rocks along Land’s End in San Francisco, turning the rocks bright white with their strong-smelling guano. Pelagic cormorants nest in very small colonies on steep cliffs and sea stacks from the Golden Gate north to Stinson Beach. Peregrine falcons are seen in their kamikaze dive, foraging along the coastal cliffs and have nested from the Golden Gate Bridge north to Muir Beach.
Colonial nesting waterbirds have found not a prison on Alcatraz Island, but inviting habitat in which to nest during the Spring and Summer months. In one of the most internationally visible settings within the National Park Sysytem, Alcatraz supports black-crowned night-herons, Brandt’s cormorants, pelagic cormorants, and pigeon guillemots - the only colonies found in San Francisco Bay for these species. Most colonial nesting waterbirds breed on offshore islands. The island’s large western gull colony represents a significant portion of its coastal breeding population in northern California.
Sandy beaches and mucky estuaries provide important habitat for migrating and wintering waterbirds and shorebirds. Tomales Bay, Bolinas Lagoon, Stinson Beach, Muir Beach, Big Lagoon, Rodeo Lagoon, Crissy Field and Ocean Beach, provide habitat for loons, grebes, scoters, numerous species of dabbling and diving ducks, gulls, terns, willets, sanderlings, and sandpipers. Federally threatened western snowy plovers overwinter in Ocean Beach. The park's mudflats provide plenty of tasty invertebrates, and estuaries provide fish and crabs galore. The San Francisco Bay is an important stopover for migrating species both due to its size and diversity of suitable habitat. Nearshore marine waters just outside the Golden Gate also provide foraging sooty shearwaters and pigeon guillemot, with thousands of birds rafting together on open water.