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
Fork-tailed storm petrel their tail. The fork-tailed storm petrel is a part of the tubenose order Procellariformes and family Hydrobatidae. The genus "Oceanodroma" arises from Ancient Greek "okeanos dromos", meaning "ocean runner", reflecting the storm petrel's distinct foraging style. Their specific name "furcata" is Latin for branched or forked, derived from "furcatus", referring to their characteristic forked tail. 2 subspecies are recognized: The major differences between the two subspecies are slight size and plumage differences, where southern populations appear somewhat smaller and darker. Southern populations also begin and end the breeding season earlier than their northern counterparts. However, no molecular genetic analysis has