Greater Crested Tern - Distribution and Habitat

Distribution and Habitat

The Greater Crested Tern occurs in tropical and warm temperate coastal parts of the Old World from South Africa around the Indian Ocean to the Pacific and Australia. The subspecies T. b. bergii and T. b. enigma breed in Southern Africa from Namibia to Tanzania, and possibly on islands around Madagascar. There is then a break in the breeding distribution of this species until Somalia and the Red Sea, and another discontinuity further east in southern India.

The Greater Crested Tern breeds on many islands in the Indian Ocean including Aldabra and Etoile in the Seychelles, the Chagos Archipelago, and Rodrigues. There are colonies on numerous Pacific islands, including Kiribati, Fiji, Tonga, the Society Islands and the Tuamotus.

The nests are located on low‑lying sandy, rocky, or coral islands, sometimes amongst stunted shrubs, often without any shelter at all. When not breeding, the Greater Crested Tern will roost or rest on open shores, less often on boats, pilings, harbour buildings and raised salt mounds in lagoons. It is rarely seen on tidal creeks or inland waters.

All populations of Greater Crested Tern disperse after breeding. When Southern African birds leave colonies in Namibia and Western Cape Province, most adults move east to the Indian Ocean coastline of South Africa. Many young birds also travel east, sometimes more than 2,000 km (1,200 mi), but others move northwards along the western coast. T. b. thalassina winters on the east African coast north to Kenya and Somalia and may move as far south as Durban. Populations of T. b. velox breeding from the Persian Gulf eastwards appear to be sedentary or dispersive rather than truly migratory, but those breeding in the Red Sea winter south along the east African coast to Kenya. T. b. cristata mostly stays within 400 km (260 mi) of its colonies, but some birds wander up to around 1,000 km (600 mi). This species has occurred as a vagrant to Hawaii, New Zealand, North Korea, Jordan, and Israel.