The great crested tern is a large tern with an extensive range. During the breeding season, the adult has a distinctive black cap with a long crest, white neck and underparts, and a grey back and upperwing. In contrast, the non-breeding adult has a white crown with limited dark spotting, but its hind-crown remains black. The large bill is greenish-yellow to yellow, and the legs are black. The juveniles primarily differ from the adults in having heavily mottled or barred brown upperparts.
They are found on coastlines in the south-east Atlantic Ocean, the Indian Ocean and the western Pacific Ocean. The great crested tern forages in the shallow waters of lagoons, coral reefs, estuaries, along all types of shoreline, and also far out to sea in open water. Nesting sites are usually located on offshore islands, low-lying coral reefs, coastal islets, spits, and lagoons.
The greater crested tern's closest relatives within its genus appear to be the lesser crested tern (T. bengalensis), and the royal tern (T. maximus).
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The greater crested tern breeds in colonies, often in association with other seabirds. It is monogamous and the pair bond is maintained through the year and sometimes in consecutive breeding seasons.
The great crested tern feeds mostly at sea by plunge diving to a depth of up to 1 m (3.3 ft), or by dipping from the surface, and food is usually swallowed in mid-air.
The diet of the great crested tern consists mainly of pelagic fish from 10 - 15 centimetres in length, but it also opportunistically takes squid, crabs, insects, baby turtles, and other aquatic prey. It typically forages in groups, flying several metres above the ocean, every now and again plunging into the water or dipping its bill just under the surface to catch unsuspecting prey. Most foraging occurs within three kilometres of the colony.
The great crested tern tends to breed in large, dense colonies or in small groups within larger mixed species colonies. Each breeding individual nests only once in any given year, with the nests being a shallow scrape in sand, gravel or coral, often packed tightly together. The clutch size is usually a singe egg, or sometimes two, which are incubated for 25 to 30 days before hatching. The chick fledges after around 38 to 40 days but remains dependent on it its parents until it is at least 4 months of age.
This species is a common visitor to Maldives.
The Jack Snipe is currently classified as ‘Least Concern’ by IUCN.
This is an adaptable species that has learned to follow fishing boats for jettisoned bycatch, and to use unusual nest sites such as the roofs of buildings and artificial islands in salt and sewage works. Human activities such as fishing, shooting and egg harvesting have caused local population declines.