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
Glaucous gull Glaucous gull The glaucous gull ("Larus hyperboreus") is a large gull, the second largest gull in the world, which breeds in Arctic regions of the Northern Hemisphere and winters south to shores of the Holarctic. The genus name is from Latin "Larus", which appears to have referred to a gull or other large seabird. The specific "hyperboreus" is Latin for "northern" from the Ancient Greek "Huperboreoi" people from the far north "Glaucous" is from Latin "glaucus" and denotes a bluish-green or grey colour. This gull is migratory, wintering from in the North Atlantic and North Pacific oceans as far south