|Gelochelidon||nilotica||affinis||Japan, s and e China through se Asia to Philippines, Sumatra, Sulawesi and Borneo|
|Gelochelidon||nilotica||aranea||e and s USA through Greater Antilles|
|Gelochelidon||nilotica||gronvoldi||French Guiana to ne Argentina|
|Gelochelidon||nilotica||nilotica||Europe, n Africa through the Middle East and sc Asia to w China and Thailand|
|Gelochelidon||nilotica||vanrossemi||s California (USA) to nw Mexico|
All black bill has sharp gonydeal angle, but no terminal hook, resembling that of small gull. Eye dark brown, crown and nape black, upperparts including rump pale grey, primaries slightly darker but wingtips whitish to pale grey. Tail and underparts white.
Races differ mainly in size, especially of bill and also in color tone of upperparts. macrotarsa is largest race, especially in bill and feet.
Listen to the sound of Gull-billed Tern
Copyright remark: Most sounds derived from xeno-canto
|wingspan min.:||76||cm||wingspan max.:||86||cm|
|size min.:||35||cm||size max.:||42||cm|
|incubation min.:||22||days||incubation max.:||23||days|
|fledging min.:||28||days||fledging max.:||35||days|
southward to winter locally from the Gulf Coast south to northern South America. G.n. Vanrossemi breeds very locally on the Pacific Coast and in the lower Colorado River delta region of southern California and northwestern Mexico, and very locally farther south in Mexico from Sinaloa to at least
Colima; it winters in western Mexico and to an unknown extent south to the Pacific Coast of Central America and possibly northwestern South America. Nunerous migrant in Suirname alomst everywhere along the coast and along more inland freshwater bodies.
Often feeds in large numbers on emerging insects over lakes, fields and grassland and even over semi desert. Winters on estuaries, lakes and salt-pans.
Chicks are white, usually unspotted. Parents attend young for 3 months. Returns to colony at 4 years old, but first breeding at 5 years.
Flies slowly and then darts swiftly down to seize prey item from surface of ground, water or vegetation. Occasionally pirates food from other terns.
Video Gull-billed Tern
copyright: J. del Hoyo