The bridled tern (''Onychoprion anaethetus'') is a

seabird Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same enviro ...

of the family

Laridae Laridae is a family of seabirds in the order Charadriiformes that includes the gulls, terns, skimmers and kittiwakes. It includes around 100 species arranged into 22 genera. They are an adaptable group of mostly aerial birds found worldwide. ...

. It is a bird of the tropical oceans. The scientific name is from

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

. The genus comes from ' meaning "claw" or "nail", and , meaning "saw". The specific ''anaethetus'' means "senseless, stupid".

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 The common tern (''Sterna hirundo'') is a seabird in the family Laridae. This bird has a circumpolar distribution, its four subspecies breeding in temperate and subarctic regions of Europe, Asia and North America. It is strongly migrator ...

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 The spectacled tern (''Onychoprion lunatus''), also known as the grey-backed tern, is a seabird in the family Laridae. Description A close relative of the bridled and sooty terns (with which it is sometimes confused), the spectacled tern is les ...

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 Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

, the Caribbean and west

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

; other races occur around the Arabian Peninsula and in

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical south-eastern region of Asia, consisting of the regions that are situated south of mainlan ...

and

Australasia Australasia is a region that comprises Australia, New Zealand and some neighbouring islands in the Pacific Ocean. The term is used in a number of different contexts, including geopolitically, physiogeographically, philologically, and ecologi ...

, but the exact number of valid subspecies is disputed. It is a rare vagrant to western

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...

. These are the four subspecies listed by the

IOC The International Olympic Committee (IOC; french: link=no, Comité international olympique, ''CIO'') is a non-governmental sports organisation based in Lausanne, Switzerland. It is constituted in the form of an association under the Swiss ...

: *''O. a. melanopterus'' – ( Swainson, 1837): Caribbean and

West Africa West Africa or Western Africa is the westernmost region of Africa. The United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali, M ...

. *''O. a. antarcticus'' – (

Lesson A lesson or class is a structured period of time where learning is intended to occur. It involves one or more students (also called pupils or learners in some circumstances) being taught by a teacher or instructor. A lesson may be either one ...

, 1831):

Red Sea The Red Sea ( ar, البحر الأحمر - بحر القلزم, translit=Modern: al-Baḥr al-ʾAḥmar, Medieval: Baḥr al-Qulzum; or ; Coptic: ⲫⲓⲟⲙ ⲛ̀ϩⲁϩ ''Phiom Enhah'' or ⲫⲓⲟⲙ ⲛ̀ϣⲁⲣⲓ ''Phiom ǹšari''; ...

Persian Gulf The Persian Gulf ( fa, خلیج فارس, translit=xalij-e fârs, lit=Gulf of Fars, ), sometimes called the ( ar, اَلْخَلِيْجُ ٱلْعَرَبِيُّ, Al-Khalīj al-ˁArabī), is a mediterranean sea in Western Asia. The bod ...

and western

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...

. *''O. a. anaethetus'' – (

Scopoli Giovanni Antonio Scopoli (sometimes Latinized as Johannes Antonius Scopolius) (3 June 1723 – 8 May 1788) was an Italian physician and naturalist. His biographer Otto Guglia named him the "first anational European" and the "Linnaeus of the Au ...

, 1786): eastern

Indian Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asia ...

, and

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...

Oceans. *''O. a. nelsoni'' – ( Ridgway, 1919): west coast of

and

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

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 The black tern (''Chlidonias niger'') is a small tern generally found in or near inland water in Europe, Western Asia and North America. As its name suggests, it has predominantly dark plumage. In some lights it can appear blue in the breeding se ...

and the

gull-billed tern The gull-billed tern (''Gelochelidon nilotica''), formerly ''Sterna nilotica'', is a tern in the family Laridae. It is widely distributed and breeds in scattered localities in Europe, Asia, northwest Africa, and the Americas. The Australian gull ...

. 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.

Various views and plumages

File:Bridledtern1.jpg, In non-breeding plumage File:Bridled Tern.jpg, Bridled tern, at

rookery A rookery is a colony of breeding animals, generally gregarious birds. Coming from the nesting habits of rooks, the term is used for corvids and the breeding grounds of colony-forming seabirds, marine mammals ( true seals and sea lions), and ...

File:bridled_tern.jpg, Juvenile on Lady Elliot Island, Queensland, Australia File:Bridled Tern flight LEI jan08.JPG, In flight Lady Elliot Island, Queensland, Australia File:Juvenile Bridled Tern Splashing.jpg, Juvenile bathing at

Perth Zoo Perth Zoo is a zoological park in South Perth, Western Australia. The zoo first opened in 1898 and by 2011 housed 1258 animals of 164 species and an extensive botanical collection. It is a full institutional member of the Zoo and Aquarium Ass ...

File:Bridled tern (Onychoprion anaethetus) Oct 2011 Karnataka Pelagic Udupi flight scape.jpg, Juvenile or adult with non-breeding plumage taking off from a sea debris perch during

Pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

expedition off coast of

Malpe Malpe is a natural port in the Udupi District in Karnataka, India. Located at the mouth of the Malpe River about six kilometers to the west of Udupi, it is an important port and a major fishing harbor on the Karnataka coast. The town of Malpe i ...

Bridled tern (Onychoprion anaethetus antarcticus) after dive composite.jpg, ''O. a. antarcticus'' after dive (composite) File:Bridled Tern from the Crossley ID Guide Britain and Ireland.jpg, ID composite File:Bridled Tern (Onychoprion anaethetus) with egg in nest under boardwalk steps at Penguin Island, November 2022 02.jpg, With egg in nest under boardwalk steps on Penguin Island, Western Australia

References

External links

Avibase
{{Taxonbar, from=Q28490 bridled tern bridled tern Birds of Central America Birds of West Africa Birds of East Africa Birds of the Middle East Birds of the Indian Ocean Birds of Southeast Asia Birds of Oceania Birds of the Pacific Ocean Pantropical fauna Birds of the Dominican Republic bridled tern bridled tern Articles containing video clips