Medium-sized gull; a bit larger than Ring-billed Gull and smaller than Herring Gull. Gray back on adults is slightly darker than Herring Gull. Adults show both red and black spots on the bill. Immatures are confusing; brownish and rather pale headed with a black-tipped pink bill. Frequents open habitats, including parking lots, beaches, inland lakes, and open ocean. Scavenges opportunistically for scraps of food. Breeds inland on islands in lakes or rivers.