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
Belcher's gull scrape in the sand or among rocks near the high tide line. There are usually three eggs averaging , pale blotched with dark olive markings. Belcher's gull is estimated to have a total population of under ten thousand individuals and an estimated distribution range of . Persecution of this bird by humans has diminished and its population is thought to be increasing. For these reasons, despite its small total population size and limited range, the International Union for Conservation of Nature considers it to be of "least concern". Belcher's gull Belcher's gull ("Larus belcheri"), also known as the band-tailed gull,