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The chemical DDT almost caused the demise of the brown pelican (Pelecanus occidentalis) in the 1960s. Pelicans exposed to DDT laid eggs with thin or non-existent shells. Since DDT was banned in 1972, brown pelicans have made a remarkable recovery. Increased efforts for seabird restoration, research, and monitoring are clearly needed in California's four national marine sanctuaries, Gulf of the Farallones, Cordell Bank, Monterey Bay, and Channel Islands. Over the past 200 years, seabird populations in California have been negatively impacted by a multitude of anthropogenic threats, especially oil pollution, gill net fishing, contaminants, disturbance at breeding colonies, loss of nesting habitats, and depredation. Populations of several resident seabird species have declined and/or experienced poor reproduction. These include ashy storm-petrel, brown pelican, common murre, marbled and Xantus's murrelets, and least tern.
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