laridae is a family of medium to large seabirds, the gulls, terns, and skimmers. gulls are typically grey or white, often with black markings on the head or wings. they have broad, longish bills and webbed feet. terns are a group of generally medium to large seabirds typically with grey or white plumage, often with black markings on the head. most terns hunt fish by diving but some pick insects off the surface of fresh water. terns are generally long-lived birds, with several species known to live more than 30 years.