Widespread and often common inland and on the coast. Adults have gray back with black wingtips. Takes four years for immatures to progress from mostly brown to white and gray; intermediate plumages are often mottled and messy. Varies incrementally across a wide geographic range. Scavenges shorelines, mudflats, plowed fields, and open ocean, picking up scraps wherever it can. Often congregates in large groups with other gulls, especially around fishing boats, beaches, piers, and landfills. Far-carrying yelping screams are a common sound of waterside habitats around the world.