Swallow-tailed gull and hunting over the open oceans, and migrating eastward to the coasts of Ecuador and Peru. The swallow-tailed gull is unique among the gulls in feeding exclusively nocturnally, mostly on fish and squid which rise to the surface at night to feed on plankton. It leaves the colony as a flock at dusk, with a great deal of screaming and display. Calls and displays are quite different from other gulls, most resembling the vocalisations of the black-legged kittiwake and Sabine's gull. The loudest and most commonly heard call is an alarm referred to as "rattle-and-whistle", a gurgling scream made with
Iceland gull Iceland gull The Iceland gull ("Larus glaucoides") is a medium size gull which breeds in the Arctic regions of Canada and Greenland; although not in Iceland (as its name suggests), where it is only seen during winter. The genus name is from Latin "Larus" which appears to have referred to a gull or other large seabird. The specific "glaucoides" denotes its resemblance to "Larus glaucus", a synonym of "Larus hyperboreus", the glaucous gull; "-oides" is Ancient Greek and means "resembling". It is migratory, wintering from in the North Atlantic as far south as the British Isles and northernmost states of