Large, dark-backed, and stout-billed gull. Adult has dark slaty gray back like Western Gull, but note the rich yellow legs. Immature plumages look much like Western Gull and other large gulls; overall brown in first year with pinkish legs, developing gray back and yellow legs in second year. Restricted range around the Gulf of California in Mexico; some disperse north to the Salton Sea in California. Favors beaches, rocky and muddy intertidal habitats, and fishing harbors.