[order] Charadriiformes | [family] Sternidae | [latin] Thalasseus bengalensis | [UK] Lesser Crested-Tern | [FR] Sterne voyageuse | [DE] Rüppellseeschwalbe | [ES] Charrán Bengalí | [IT] Sterna di Rüppel | [NL] Bengaalse Stern

Bengaalse Stern determination

copyright: Tom Tarrant

The Elegant Tern is a fairly large, slim tern, with a long, orange, slightly drooping bill. It has narrow, angled wings, a deeply forked tail, and a shaggy crest. The adult in breeding plumage has a gray mantle, white breast and belly, and white face with a black, crested cap. The legs are black. The adult in non-breeding plumage is similar, but with a white forehead that darkens to streaky black, as if the cap has receded. Juveniles appear similar to non-breeding adults, but their legs are yellow.

The species inhabits tropical and subtropical sandy and coral coasts and estuaries, breeding on low-lying offshore islands, coral flats, sandbanks and flat sandy beaches, foraging in the surf and over offshore waters.

Sterna bengalensis has a predominantly tropical and subtropical breeding distribution, although two or three pairs do breed in Europe at two sites in north-eastern Spain and northern Italy. Although this tiny European population probably remained broadly stable overall during 1990-2000, its size could render it susceptible to the risks affecting small populations. Nevertheless, as it is marginal to a far larger non- European population, the species is provisionally evaluated as Secure.
The details of this species's movements are poorly known although some breeding populations appear to be migratory. The species breeds in large dense colonies of up to 20,000 pairs often with other species. It is gregarious throughout the year, foraging in single- or mixed-species flocks up to 400 individuals. Accidental breeding has also been reported in Italy and France.

Elegant Terns forage by hovering over shallow water and then plunging into the water after fish. This tern can transport a single fish at a time crosswise in its bill. Elegant Terns forage on a variety of different schooling fish, with northern anchovy (Engraulis mordax) being their most important prey item. Other prey species include sardines, silversides, gobies, mackerels, and rarely, crustaceans. When feeding in flocks, these gregarious terns call frequently.

This species has a large range, with an estimated global Extent of Occurrence of 100,000-1,000,000 km2. It has a large global population estimated to be 180,000-210,000 individuals (Wetlands International 2002). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern. [conservation status from birdlife.org]

A strongly social bird, this tern nests in tight groups. Like many other terns, Elegant Tern nests consist of a shallow scrape on the ground. Their typical clutch size is one egg, buff to white marked with dark brown, which is probably incubated by both parents. After a period of at least three weeks, the single chick hatches and spends a few days in the nest before joining a creche—a group of young birds who are still fed by their own parents. Post-fledging parental care lasts up to six months, during which time the chicks learn foraging skills.

Inadequately known owing to lack of ringing studies. Migratory in Mediterranean, with post-breeding movement to Morocco and Senegambia, but only partly migratory in most range. Middle East birds pass E coast of Africa to Natal. N Indian Ocean populations partly migratory. Vagrant inland.