Slightly larger than Black-headed Gull, more similar to Mew Gull in size and shape but bill stouter. Adult is distinctive, the only small gull with snow-white wingtips; breeding plumage has black hood. Nonbreeding and immature have distinctive, dark horizontal face mask. Juvenile has mottled brownish back, which molts to pale gray by winter. Tends to be uncommon to locally fairly common; often found with flocks of Black-headed Gulls and Mew (Common) Gulls.