Adult Plumage: The head, neck and underparts are white; the relatively short bill is yellow with a dark ring; the back and wings are silver gray; and the legs are yellow. The eyes are yellow with red rims. This gull takes three years to reach its breeding plumage; its appearance changes with each fall moult. Juvenal plumage: Dirty, grayish brown head, back, and chest. Back feathers with light tips, giving a scaly appearance. Underparts streaked or barred, especially on the flanks. Tail gray with black band near tip. Wingtips black. Bill black with lighter base. Eyes dark. Legs pinkish.
A familiar parking lot gull, the Ring-billed Gull breeds primarily inland in North America. It can be found along the coasts, but many of these "seagulls" never see anything except fresh water all their lives. Their breeding habitat is near lakes, rivers or the coast in Canada and the northern United States. They nest colonially on the ground, often on islands. This bird tends to be faithful to its nesting site, if not its mate, from year to year. They are migratory and most move south to the Gulf of Mexico and the Atlantic and Pacific coasts of North America, also the Great Lakes.
These birds forage in flight or pick up objects while swimming, walking or wading. They also steal food from other birds and frequently scavenge. They are omnivorous; their diet may include insects, fish, grain, eggs, earthworms and rodents. These birds are opportunistic and have adapted well to taking food discarded or even left unattended by people. It is regarded as a pest by many beach-goers because of its willingness to steal unguarded food on highly crowded beaches.