Bridled Tern
Onychoprion anaethetus
褐翅燕鸥
Introduction
A seabird in the family Laridae. Inhabits tropical oceans globally, with a migratory and dispersive range extending through tropical waters in winter. Distinguished by markedly marine habits compared to most terns, breeding exclusively on rocky islands in colonies. Four subspecies are recognized: O. a. melanopterus in the Caribbean and West Africa, O. a. antarcticus in the Red Sea and western Indian Ocean, O. a. anaethetus in the eastern Indian and Pacific Oceans, and O. a. nelsoni along the west coast of Mexico and Central America.
Description
A medium-sized tern measuring 30–32 cm in length with a wingspan of 77–81 cm, similar in size to the common tern but more heavily built. The wings and deeply forked tail are long. Upperparts are dark grey, while underparts are white. The forehead and eyebrows are white, forming a striking white collar on the hindneck. Legs and bill are black. Juveniles appear scaly grey above and pale below.
Identification
Unlikely to be confused with any tern species except the similarly dark-backed sooty tern and the spectacled tern from the Tropical Pacific. The bridled tern is paler-backed than the sooty tern (though not as pale as the grey-backed terns) and shows a narrower white forehead. The pale neck collar is a distinguishing feature that the sooty tern lacks.
Distribution & Habitat
Migratory and dispersive throughout tropical oceans. The Atlantic subspecies melanopterus breeds in Mexico, the Caribbean, and West Africa. Other populations occur around the Arabian Peninsula, Southeast Asia, and Australasia. Markedly marine in habits, it rarely approaches land except to breed. A rare vagrant to western Europe.
Behavior & Ecology
Feeds by plunge-diving for fish in marine environments, typically diving directly rather than using the stepped-hover technique of the Arctic tern. Also picks prey from the surface. Breeds in colonies on rocky islands, nesting in a ground scrape or hole with a single egg. Courtship involves the male offering fish to the female.
Conservation
Not available
Source: Wikipedia · CC BY-SA 3.0
Taxonomy
- Order
- Charadriiformes
- Family
- Laridae
- Genus
- Onychoprion
- eBird Code
- briter1
Subspecies (4)
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Onychoprion anaethetus anaethetus
breeds islets from west of Thailand eastward through Ryukyu Islands (southern Japan) and Philippines, and southward to northern Australia (southwestern Australia to northeastern New South Wales) and Samoa
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Onychoprion anaethetus antarcticus
breeds islets from Red Sea southward to Malagasy region and Indian Ocean eastward to the Maldives and Chagos Islands, and locally islets off Maharashtra (western India) and Sri Lanka
-
Onychoprion anaethetus melanopterus
breeds islets off southern Morocco, Mauritania, and Senegal, and Gulf of Guinea, and throughout Caribbean; non-breeders range northward to New England in Gulf Stream
-
Onychoprion anaethetus nelsoni
breeds islets off western Mexico, Central America, and Ecuador
Data Sources
Species description from Wikipedia, licensed under CC BY-SA 3.0.
Bird images and sounds sourced from GBIF, contributed by citizen scientists worldwide under Creative Commons licenses.
Taxonomy data from AviList 2025.