This is the only fully nocturnal gull and seabird in the world, preying on squid and small fish which rise to the surface at night to feed on plankton. The swallow-tailed gull is a near endemic breeding bird of the Glaapagos Islands, although a few pairs nest on Malpelo Island off the coast of Colombia. When not breeding, this speies is totally pelagic, flying and hunting over the open ocean, and migrating eastward to the coasts of Ecuador and Peru.