The bridled tern (''Onychoprion anaethetus'')Sometimes the name is (wrongly?) spelled as ''S. anaestheta'', for instance in: is a

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

of the family Laridae. 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 classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

. 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 Temperateness, temperate and subarctic regions of Europe, Asia and North America. It is stron ...

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 l ...

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 In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

''melanopterus'' breeds in

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

, the

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

and west

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

; other races occur around the

Arabian Peninsula The Arabian Peninsula (, , or , , ) or Arabia, is a peninsula in West Asia, situated north-east of Africa on the Arabian plate. At , comparable in size to India, the Arabian Peninsula is the largest peninsula in the world. Geographically, the ...

and in

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

and

Australasia Australasia is a subregion of Oceania, comprising Australia, New Zealand (overlapping with Polynesia), and sometimes including New Guinea and surrounding islands (overlapping with Melanesia). The term is used in a number of different context ...

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

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

. These are the four subspecies listed by the IOC: *''O. a. melanopterus'' – ( Swainson, 1837):

and

West Africa West Africa, also known as Western Africa, is the westernmost region of Africa. The United Nations geoscheme for Africa#Western Africa, United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Gha ...

. *''O. a. antarcticus'' – ( Lesson, 1831):

Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...

Persian Gulf The Persian Gulf, sometimes called the Arabian Gulf, is a Mediterranean seas, mediterranean sea in West Asia. The body of water is an extension of the Arabian Sea and the larger Indian Ocean located between Iran and the Arabian Peninsula.Un ...

and western

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

. *''O. a. anaethetus'' – ( Scopoli, 1786): eastern Indian, 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 the definition, to Antarctica in the south, and is bounded by the cont ...

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

and

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

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 Arctic tern (''Sterna paradisaea'') is a tern in the family Laridae. This bird has a circumpolar breeding distribution covering the Arctic and sub-Arctic regions of Europe (as far south as Brittany), Asia, and North America (as far south ...

. 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 rooks, and more broadly a colony of several types 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-fo ...

File:bridled_tern.jpg, Juvenile on Lady Elliot Island, Queensland,

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

File:Bridled Tern flight LEI jan08.JPG, In flight Lady Elliot Island, Queensland,

File:Juvenile Bridled Tern Splashing.jpg, Juvenile bathing at

Perth Zoo Perth Zoo is a zoological park in South Perth, Western Australia, 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 me ...

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. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

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
{{Authority control 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 Fauna of the Pantropical realm Birds of the Dominican Republic bridled tern bridled tern Articles containing video clips