The wedge-tailed shearwater (''Ardenna pacifica'') is a medium-large

shearwater Shearwaters are medium-sized long-winged seabirds in the petrel family Procellariidae. They have a global marine distribution, but are most common in temperate and cold waters, and are pelagic outside the breeding season. Description These tube ...

in the

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 ...

family

Procellariidae The family (biology), family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the diving petrels, the prion (bird), prions, and the shearwaters. This family is part of the bird order (biology), orde ...

. It is one of the shearwater species that is sometimes referred to as a muttonbird, like the

sooty shearwater The sooty shearwater (''Ardenna grisea'') is a medium-large shearwater in the seabird family Procellariidae. In New Zealand, it is also known by its Māori language, Māori name , and is harvested by Māori people for muttonbirding, muttonbird, l ...

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

and the

short-tailed shearwater The short-tailed shearwater or slender-billed shearwater (''Ardenna tenuirostris''; formerly ''Puffinus tenuirostris''), also called yolla or moonbird, and commonly known as the muttonbird in Australia, is the most abundant seabird species in A ...

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 ...

. It is found throughout the

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

Pacific and

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), ...

s, roughly between

latitude In geography, latitude is a geographic coordinate system, geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at t ...

s 35°N and 35°S. It breeds on the islands off

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, on the Islas Revillagigedo, the

Hawaiian Islands The Hawaiian Islands () are an archipelago of eight major volcanic islands, several atolls, and numerous smaller islets in the Pacific Ocean, North Pacific Ocean, extending some from the Hawaii (island), island of Hawaii in the south to nort ...

, the

Seychelles Seychelles (, ; ), officially the Republic of Seychelles (; Seychellois Creole: ), is an island country and archipelagic state consisting of 155 islands (as per the Constitution) in the Indian Ocean. Its capital and largest city, Victoria, ...

, the

Northern Mariana Islands The Northern Mariana Islands, officially the Commonwealth of the Northern Mariana Islands (CNMI), is an Territories of the United States, unincorporated territory and Commonwealth (U.S. insular area), commonwealth of the United States consistin ...

, and off Eastern and Western

Taxonomy

The wedge-tailed shearwater was formally described in 1789 by the German naturalist

Johann Friedrich Gmelin Johann Friedrich Gmelin (8 August 1748 – 1 November 1804) was a German natural history, naturalist, chemist, botanist, entomologist, herpetologist, and malacologist. Education Johann Friedrich Gmelin was born as the eldest son of Philipp F ...

in his revised and expanded edition of

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

's ''

Systema Naturae ' (originally in Latin written ' with the Orthographic ligature, ligature æ) is one of the major works of the Sweden, Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the syste ...

''. He placed it with the

petrel Petrels are tube-nosed seabirds in the phylogenetic order Procellariiformes. Description Petrels are a monophyletic group of marine seabirds, sharing a characteristic of a nostril arrangement that results in the name "tubenoses". Petrels enco ...

s in the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Procellaria Procellaria is a genus of Southern Ocean long-winged seabirds related to prions, and within the order Procellariiformes. The black petrel (''Procellaria parkinsoni'') ranges in the Pacific Ocean, and as far north as Central America. The spec ...

'' and coined the

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, altho ...

''Procellaria pacifica''. Gmelin based his description on the "Pacific petrel" that had been described in 1785 by the English ornithologist John Latham in his book ''A General Synopsis of Birds''. The type locality was designated as the

Kermadec Islands The Kermadec Islands ( ; ) are a subtropical island arc in the South Pacific Ocean northeast of New Zealand's North Island, and a similar distance southwest of Tonga. The islands are part of New Zealand. They are in total area and uninhabit ...

by Gregory Mathews in 1912. The wedge-tailed shearwater is now one of seven species placed in the genus '' Ardenna'' that introduced in 1853 by

Ludwig Reichenbach Heinrich Gottlieb Ludwig Reichenbach (8 January 1793 – 17 March 1879) was a German botanist, ornithologist and illustrator. It was he who first requested Leopold and Rudolf Blaschka, Leopold Blaschka to make a set of glass marine invertebrate m ...

. The species is

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...

: no

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 ...

are recognised. A

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

study published in 2022 found that the wedge-tailed shearwater was

sister A sister is a woman or a girl who shares parents or a parent with another individual; a female sibling. The male counterpart is a brother. Although the term typically refers to a familial relationship, it is sometimes used endearingly to ref ...

to Buller's shearwater.

Description

The wedge-tailed shearwater is the largest of the tropical shearwaters. The two colour morphs of the species are dark and pale; the pale morphs predominate in the

North 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 contine ...

, the dark morph elsewhere. However, both morphs exist in all populations, and bear no relation to sex or breeding condition. The pale morph has grey-brown plumage on the back, head, and upper wing, and whiter plumage below. The darker morph has the same dark grey-brown plumage over the whole body. The species' common name is derived from the large, wedge-shaped tail, which may help the species glide. The bill is dark and legs are salmon pink, with the legs set far back on the body (in common with the other shearwaters) as an adaptation for swimming. This species is related to the pan-Pacific Buller's shearwater, which differs much in colour pattern, but also has a wedge tail and a thin, black bill. They make up the ''Thyellodroma'' group, a

superspecies In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

of the large shearwaters that were for a long time included in the genus ''Puffinus''.

Behaviour and ecology

Food and feeding

Wedge-tailed shearwaters feed

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 ...

ally on

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

, and crustaceans. Their diet is 66% fish, of which the most commonly taken is

goatfish The goatfishes are ray-finned fish of the family Mullidae, the only family in the suborder Mulloidei of the order Syngnathiformes. The family is also sometimes referred to as the red mullets, which also refers more narrowly to the genus '' Mul ...

. The species was thought to mostly take food from surface feeding, but observations of feeding wedge-tails suggested that contact-dipping, where birds flying close to the surface snatch prey from the water was the most commonly used hunting technique. However, a 2001 study which deployed maximum depth recorders found that 83% of wedge-tails dived during foraging trips with a mean maximum depth of and that they could achieve a depth of .

Breeding

The wedge-tailed shearwater breeds in

colonies A colony is a territory subject to a form of foreign rule, which rules the territory and its indigenous peoples separated from the foreign rulers, the colonizer, and their '' metropole'' (or "mother country"). This separated rule was often or ...

on small tropical islands. Breeding seasons vary depending on location, with synchronised breeding seasons more common at higher latitudes. Northern Hemisphere birds begin breeding around February, and Southern Hemisphere birds begin around September. Wedge-tailed shearwaters display natal

philopatry Philopatry is the tendency of an organism to stay in or habitually return to a particular area. The causes of philopatry are numerous, but natal philopatry, where animals return to their birthplace to breed, may be the most common. The term derives ...

, returning to their natal colony to begin breeding at the age of four. Wedge-tailed shearwaters are

monogamous Monogamy ( ) is a relationship of two individuals in which they form a mutual and exclusive intimate partnership. Having only one partner at any one time, whether for life or serial monogamy, contrasts with various forms of non-monogamy (e.g. ...

, forming a pair bond that lasts for several years. Divorce between pairs occurs after breeding seasons that end in failure. Nesting occurs either in burrows or sometimes on the surface under cover. Pairs call frequently as a pair, both to reinforce the pair bond and warn intruders away from their territory. Parents also call to their chicks. The call is long, with an inhaling component (OOO) and exhaling component (err); their Hawaiian name '' 'ua'u kani'' means moaning petrel. Both sexes participate in digging a burrow, or repairing the burrow from last year. Nesting burrows of other species are also used. The breeding season of the Bonin petrel in Hawaii is timed to avoid that of the wedge-tail; in years where Bonin petrel chicks are still in burrows when wedge-tails return to begin breeding, these chicks are killed or evicted. It attends these colonies nocturnally, although nonbreeding wedge-tails are often seen at the surface throughout the day and breeding birds rest outside their burrows before laying. Both sexes undertake a prelaying exodus to build up energy reserves; this usually lasts around 28 days. A single egg is laid, if that egg is lost, then the pair will not attempt another that season. After laying, the male usually undertakes the first incubation stint. Both sexes incubate the egg, in stints that can last up to 13 days. Incubation takes around 50 days. After hatching, the chick is brooded for up to 6 days, until it is able to thermoregulate, after which it is left alone in the nest while both parents hunt for food. It is initially fed with stomach oil, an energy-rich, waxy oil of digested prey created in the parent's gut; later, it is fed both solids and stomach oil. Like many procellariids, wedge-tailed shearwater parents alternate long and short trips to provide food, with the parents alternating between short foraging trips (1–4 days) and long trips (about 8 days), the two parents coordinating their feeding effort. Chicks increase in size to (larger than the adults), then drop to around before fledging. Fledging occurs after 103–115 days, after which the chick is independent of the adult. Known breeding colonies include: * Pacific Missile Range Facility, Kauai, Hawaii * Heron Island, Australia *

Lady Elliot Island Lady Elliot Island is the southernmost coral cay of the Great Barrier Reef, Australia. The island lies north-east of Bundaberg and covers an area of approximately . It is part of the Capricorn and Bunker Group of islands and is owned by the C ...

, Australia * Lady Musgrave Island, Australia *

Lord Howe Island Lord Howe Island (; formerly Lord Howe's Island) is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, part of the Australian state of New South Wales. It lies directly east of mainland Port ...

, Australia * Montague Island, Southern

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

, Australia * North West Island, Australia * Muttonbird Island,

Coffs Harbour Coffs Harbour, locally nicknamed Coffs, is a coastal city on the Mid North Coast of New South Wales, Australia, north of Sydney, and south of Brisbane. It is one of the largest urban centres on the North Coast, with a population of 78,759 a ...

, Northern New South Wales, Australia * Mānana Island,

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

, United States * Maui, Hawaii, United States * Mokuauia Island, Hawaii, United States * Kupikipiki’o Pt., Hawaii, United States * Ilot Maitre, Noumea, New Caledonia * Round Island,

Mauritius Mauritius, officially the Republic of Mauritius, is an island country in the Indian Ocean, about off the southeastern coast of East Africa, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Ag ...

* Ka'ena Point,

Oahu Oahu (, , sometimes written Oahu) is the third-largest and most populated island of the Hawaiian Islands and of the U.S. state of Hawaii. The state capital, Honolulu, is on Oahu's southeast coast. The island of Oahu and the uninhabited Northwe ...

* Mañagaha,

Saipan Saipan () is the largest island and capital of the Northern Mariana Islands, an unincorporated Territories of the United States, territory of the United States in the western Pacific Ocean. According to 2020 estimates by the United States Cens ...

, CNMI *

San Benedicto Island San Benedicto, formerly Isla de los Inocentes, is an uninhabited island, and third largest island of the Revillagigedo Islands, located in the Pacific Ocean. It is 4.8 km by 2.4 km in size, with an area 10 km². It is of volcano, ...

Revillagigedo Islands The Revillagigedo Islands (, ) or Revillagigedo Archipelago are a group of four volcanic islands in the Pacific Ocean, known for their unique ecosystem. They lie approximately from Socorro Island south and southwest of Cabo San Lucas, the sout ...

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 ...

* Alphonse Island, Republic of Seychelles * Bijoutier Island, Republic of Seychelles

Gallery

A juvenile wedge-tailed shearwater.jpg, Juvenile, Kilauea,

Kauai Kauai (), anglicized as Kauai ( or ), is one of the main Hawaiian Islands. It has an area of 562.3 square miles (1,456.4 km2), making it the fourth-largest of the islands and the 21st-largest island in the United States. Kauai lies 73 m ...

W-tail.JPG, Profile in flight, Hawaiian Islands

References

External links

BirdLife species factsheet
* California Bird Records Committee

* USFWS, Midway Atoll NWR
Wedge-tailed shearwater
* Frank O'Connor's Birding Western Australia

{{Taxonbar, from=Q27074601

wedge-tailed shearwater The wedge-tailed shearwater (''Ardenna pacifica'') is a medium-large shearwater in the seabird family Procellariidae. It is one of the shearwater species that is sometimes referred to as a muttonbird, like the sooty shearwater of New Zealand and ...

Birds of the Indian Ocean Birds of the Pacific Ocean Subterranean nesting birds

Wedge-tailed shearwater The wedge-tailed shearwater (''Ardenna pacifica'') is a medium-large shearwater in the seabird family Procellariidae. It is one of the shearwater species that is sometimes referred to as a muttonbird, like the sooty shearwater of New Zealand and ...