Large, stocky gull of the North Pacific. Generally fairly pale and uniform-looking; at all ages, note wingtips and back are approximately the same color. Takes four years for immatures to progress from mostly brown to fully white and gray adult plumage; intermediate plumages are often mottled and messy. Most immatures look frosty grayish-brown with smooth patterning. Found in coastal areas, including beaches, mudflats, and even city parks. Identification is complicated by frequent hybridization with Western, Herring, and Glaucous Gulls in various parts of range. Pure birds can be difficult to find and identify with certainty, and many intermediate birds are best left unidentified.