''Onychoprion'', the "brown-backed terns", is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 ...

s in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

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. T ...

. The genus 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 peri ...

, "claw" or "nail", and , "saw".

Species

Although the genus was first described in 1832 by

Johann Georg Wagler Johann Georg Wagler (28 March 1800 – 23 August 1832) was a German herpetologist and ornithologist. Wagler was assistant to Johann Baptist von Spix, and gave lectures in zoology at the Ludwig Maximilian University of Munich after it was moved ...

the four species in the genus were until 2005 retained in the larger genus ''

Sterna ''Sterna'' is a genus of terns in the bird family Laridae. The genus used to encompass most "white" terns indiscriminately, but mtDNA sequence comparisons have recently determined that this arrangement is paraphyletic. It is now restricted to t ...

'', the genus that holds most terns.Bridge, E. S.; Jones, A. W. & Baker, A. J. (2005)
A phylogenetic framework for the terns (Sternini) inferred from mtDNA sequences: implications for taxonomy and plumage evolution
. ''Molecular Phylogenetics and Evolution'' 35: 459–469. Three of the four species are

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

, and one has a sub-polar breeding range. The

sooty tern The sooty tern (''Onychoprion fuscatus'') is a seabird in the family Laridae. It is a bird of the tropical oceans, returning to land only to breed on islands throughout the equatorial zone. Taxonomy The sooty tern was described by Carl Linnaeu ...

has a pan-tropical distribution; the

bridled tern The bridled tern (''Onychoprion anaethetus'') is a seabird of the family Laridae. It is a bird of the tropical oceans. The scientific name is from Ancient Greek. The genus comes from ' meaning "claw" or "nail", and , meaning "saw". The specific ...

also breeds across the Tropical

Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe an ...

and

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 th ...

but in the central

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 continen ...

it is replaced by 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 ...

. The

Aleutian tern The Aleutian tern (''Onychoprion aleuticus'') is a migratory bird living in the subarctic region of the globe most of the year. It is frequently associated with the Arctic tern, which it closely resembles. While both species have a black cap, th ...

breeds around

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

and

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of ...

but winters in the tropics around

South East 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 mainland ...

. ''Manutara'' is the

Rapa Nui language Rapa Nui or Rapanui (, Rapa Nui: , Spanish: ), also known as Pascuan () or ''Pascuense'', is an Eastern Polynesian language of the Austronesian language family. It is spoken on the island of Rapa Nui, also known as ''Easter Island''. The isl ...

name for spectacled and sooty terns. Both arrive at

Easter Island Easter Island ( rap, Rapa Nui; es, Isla de Pascua) is an island and special territory of Chile in the southeastern Pacific Ocean, at the southeasternmost point of the Polynesian Triangle in Oceania. The island is most famous for its nearl ...

and hatch their eggs on the island called

Motu Nui Motu Nui (''large island'' in the Rapa Nui language) is the largest of three islets just south of Easter Island and is the List of extreme points of Chile, most westerly place in Chile and all of South America. All three islets have seabirds, ...

, an event that was used for an annual rite called

Tangata manu The ''Tangata manu'' ("bird-man," from "human beings" + "bird") was the winner of a traditional competition on Rapa Nui (Easter Island). The ritual was an annual competition to collect the first sooty tern () egg of the season from the islet of ...

References

{{Taxonbar, from=Q1088377 Bird genera Terns