Sabine's gull

The Sabine's gull (Xema sabini), also known as the fork-tailed gull or xeme, is a small gull. Its generic placement is disputed; some authors treat it as the sole species in the genus Xema as Xema sabini, while others retain it in the genus Larus as Larus sabini. It breeds in the Arctic and has a circumpolar distribution through northernmost North America and Eurasia. It migrates south in autumn; most of the population winters at sea in the Pacific off western South America in the cold waters of the Humboldt Current, while Greenland and eastern Canadian birds cross the Atlantic by way of the westernmost fringes of Europe to winter off southwest Africa in the cold waters of the Benguela Current. Occasionally individual Sabine's gulls can be seen off other coasts such as the northeastern United States or further east in Europe, typically following autumn storms. It is recorded often enough inland in North America, Europe, and even Siberia, that it has been said to exhibit "cross-continental migration" in addition to migration at sea.