Thai National Parks

Birds of Thailand

Species of Thailand

Bridled tern

Thai: นกนางนวลแกลบคิ้วขาว, nok naang-nuan klaep khiu khao

Binomial name: Onychoprion anaethetus, Giovanni Antonio Scopoli, 1786

The bridled tern (Onychoprion anaethetus, formerly Sterna anaethetus - see Bridge et al., 2005) is a seabird of the tern family Sternidae. It is a bird of the tropical oceans.

Description

This is a medium-sized tern, at 30–32 cm in length and with a 77–81 cm wingspan similar to the common tern in size, but more heavily built. The wings and deeply forked tail are long, and it has dark grey upperparts and white underparts. The forehead and eyebrows are white, as is a striking collar on the hindneck. It has black legs and bill. Juvenile bridled terns are scaly grey above and pale below.

This species is unlikely to be confused with any tern apart from the similarly dark-backed sooty tern and the spectacled tern from the Tropical Pacific. It is paler-backed than that sooty, (but not as pale as the grey-backed) and has a narrower white forehead and a pale neck collar.

Distribution and movements

This bird is migratory and dispersive, wintering more widely through the tropical oceans. It has markedly marine habits compared to most terns. The Atlantic subspecies melanopterus breeds in Mexico, the Caribbean and west Africa; other races occur around the Arabian Peninsula and in Southeast Asia and Australasia, but the exact number of valid subspecies is disputed. It is a rare vagrant to western Europe.

Breeding

This species breeds in colonies on rocky islands. It nests in a ground scrape or hole and lays one egg. It feeds by plunge-diving for fish in marine environments, but will also pick from the surface like the black tern and the gull-billed tern. It usually dives directly, and not from the "stepped-hover" favoured by the Arctic tern. The offering of fish by the male to the female is part of the courtship display.

This article uses material from Wikipedia released under the Creative Commons Attribution-Share-Alike Licence 3.0. Eventual photos shown in this page may or may not be from Wikipedia, please see the license details for photos in photo by-lines.

Scientific classification

Kingdom
Animalia
Phylum
Chordata
Class
Aves
Order
Charadriiformes
Family
Sternidae
Genus
Onychoprion
Species
Onychoprion anaethetus

Common names

  • English: Bridled tern
  • French: Sterne bridée
  • Thai: นกนางนวลแกลบคิ้วขาว, nok naang-nuan klaep khiu khao

Subspecies

  • Onychoprion anaethetus anaethetus, Scopoli, 1786

    Range: Eastern Indian, and Pacific Oceans.

  • Onychoprion anaethetus antarcticus, René Primevère Lesson, 1831

    Range: Red Sea, Persian Gulf and western Indian Ocean.

  • Onychoprion anaethetus melanopterus, William John Swainson, 1837

    Range: Caribbean and West Africa.

  • Onychoprion anaethetus nelsoni, Robert Ridgway, 1919

    Range: West coast of Mexico and Central America.

Synonyms

  • Onychoprion anaethetus subspecies anaethetus, Les Christidis & Walter E. Boles (2008)
  • Onychoprion anaethetus, AOU Checklist (1998)
  • Sterna anaethetus, Giovanni Antonio Scopoli (1786)

Conservation status

Least Concern (IUCN3.1)

Least Concern (IUCN3.1)

Distribution map of Bridled tern, Onychoprion anaethetus in Thailand

Range map of Onychoprion anaethetus in Thailand

Important note; our range maps are based on limited data we have collected. The data is not necessarily accurate or complete.

Special thanks to Ton Smits, Parinya Pawangkhanant, Ian Dugdale and many others for their contribution for range data.

Contribute or get help with ID

Please help us improving our species range maps. To add a new location to the range map we need a clear image of the specimen you have encountered. No problem if you do not know the species, we will do our best to identify it for you.

For the location, please provide the district name or the national park/ wildlife sanctuary name.

Please post your images to our Thai Species Identification Help group on Facebook.