The California Gull (Larus californicus) is a medium-sized gull, similar in appearance to the Herring Gull. In California, the California Gull has been protected due to declining numbers at their historic California breeding colony at Mono Lake. However, in recent decades this species has been breeding successfully in the southern portion of San Francisco Bay, where it did not historically breed, and has undergone exponential population growth. This population boom has resulted in large resident flocks of gulls that will opportunistically prey on other species, particularly the eggs and nestlings of other birds.

They are migratory, most moving to the Pacific coast in winter being the time when this bird is regularly found in western California and in this case, Morro Bay.