Large, dark-backed, and stout-billed gull found in the Gulf of California; mainly in late summer, though some disperse north to Salton Sea, California. Favors beaches, rocky and muddy intertidal habitats, and fishing harbors. 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 1st year and with pinkish legs, developing gray back and yellow legs in 2nd year.