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Gull-billed Terns are medium-sized terns. During the breeding season they have a black cap, white front (throat, neck, chest, belly and vent) and grey wings. The black eyes are surrounded by the black cap, while the frons (base of the bill) is also black. The stout bill is black, the short legs and feet are also black. In eclipse the cap becomes mostly white, with grey patches remaining behind the eyes and some mottled black-and-white remaining at the back of the head. Juveniles are mottled grey, with a mottled cap and black eye patches.

Twitcher's tip

Compared to other, similar terns, the Gull-billed Tern has the most massive black bill (hence its name).

Both the Gull-billed Tern and the Australian Tern. have been moved from the genus "Sterna" into "Gelochelidon".

In addition, the Australian Tern has now been given full species status and is no longer considered to be race "macrotarsa" of the Gull-billed Tern.

The overall distribution of this species can be assessed, and specific locations where birds have been spotted can be found, based on individual sighting reports submitted by birdwatchers to ebird.org .

The global distribution of the Gull-billed Tern is available HERE .

Gull-billed Terns are a global species, of which there are 5 extant races. All races are dispersive after the end of the breeding season, and those breeding in the northern hemisphere are the most strongly migratory races. Nominate race "nilotica" have a very extended breeding range, from Europe and North Africa in the West, through the Middle East and southern-central Asia to western China and Thailand in the East. The breeding range of the Asian race "affinis" extends from parts of Indonesia (Borneo, Sulawesi, Sumatra) through the Philippines and south-eastern Asia, South and East China up to Japan in the East. The three other races, "aranea", "vanrossemi" and "gronvoldi" are found in various parts of the Americas (for details see, e.g., Wikipedia). The northern races tend to spend the winters farther South, e.g. in southern America, in Africa, or south-eastern Asia.

Occasionally, migratory Gull-billed Terns of the Asian race "affinis" can be found primarily along the North coast of the Australian continent.

Gull-billed Terns can be found above coastal waters, but also in tidal flats and inland, in the shallows of freshwater lakes, including ephemeral lakes and ephemeral wetlands.

Race "nilotica"

Race "affinis"