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 tub ...

in the

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 ...

family

Procellariidae The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the diving petrels, the prions, and the shearwaters. This family is part of the bird order Procellariiformes (or tubenoses), which als ...

. 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 name , and as muttonbird, like its relatives the wedge-tailed shearwater (''A. pacificus ...

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

and the short-tailed shearwater of Australia. It ranges throughout the

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 ...

Pacific 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 t ...

s, roughly between

latitude In geography, latitude is a 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 the south pole to 90° at the north pol ...

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

Islas Revillagigedo The Revillagigedo Islands ( es, Islas Revillagigedo, ) 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 C ...

, the Hawaiian Islands, the

Seychelles Seychelles (, ; ), officially the Republic of Seychelles (french: link=no, République des Seychelles; Creole: ''La Repiblik Sesel''), is an archipelagic state consisting of 115 islands in the Indian Ocean. Its capital and largest city, ...

, the

Northern Mariana Islands The Northern Mariana Islands, officially the Commonwealth of the Northern Mariana Islands (CNMI; ch, Sankattan Siha Na Islas Mariånas; cal, Commonwealth Téél Falúw kka Efáng llól Marianas), is an unincorporated territory and commonw ...

, and off Eastern and Western Australia.

Taxonomy

The wedge-tailed shearwater was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...

's '' Systema Naturae''. He placed it with the petrels in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

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 specta ...

'' and coined the binomial name ''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 ( mi, Rangitāhua) 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 ar ...

Gregory Mathews Gregory Macalister Mathews CBE FRSE FZS FLS (10 September 1876 – 27 March 1949) was an Australian-born amateur ornithologist who spent most of his later life in England. Life He was born in Biamble in New South Wales the son of Robert H. M ...

in 1912. The wedge-tailed shearwater is now one of seven species placed in the genus ''

Ardenna ''Ardenna'' is a genus of seabirds in the family Procellariidae. These medium-sized shearwater species were formerly included in the genus ''Puffinus''. Taxonomy A phylogenetic analysis using mitochondrial DNA published in 2004 found that ''Puff ...

'' that introduced in 1853 by Ludwig Reichenbach. 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 "unispe ...

: no subspecies are recognised. A molecular phylogenetic study published in 2022 found that the wedge-tailed shearwater was

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

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 definition, to Antarctica) in the south, and is bounded by the continen ...

, 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 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 (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

ally on

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...

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

goatfish The goatfishes are perciform fish of the family Mullidae. The family is also sometimes referred to as the red mullets, which also refers more narrowly to the genus '' Mullus''. The family name and the English common name mullet derived from La ...

. 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 In modern parlance, a colony is a territory subject to a form of foreign rule. Though dominated by the foreign colonizers, colonies remain separate from the administration of the original country of the colonizers, the '' metropolitan state'' ...

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 derive ...

, returning to their natal colony to begin breeding at the age of four. Procellariidae - Puffinus pacificus (Wedge-tailed Shearwaters)

Wedge-tailed shearwaters are monogamous, 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 The Bonin petrel or'' nunulu'' (''Pterodroma hypoleuca'') is a seabird in the family Procellariidae. It is a small gadfly petrel that is found in the northwest Pacific Ocean. Its secretive habits, remote breeding colonies and limited range have re ...

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 is the stage in a flying animal's life between hatching or birth and becoming capable of flight. This term is most frequently applied to birds, but is also used for bats. For altricial birds, those that spend more time in vulnerable c ...

. 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 *

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 P ...

, Australia * Montague Island, Southern

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

, Australia * North West Island, Australia * Muttonbird Island, Coffs Harbour, Northern New South Wales, Australia * Mānana Island,

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...

, 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 ( ; french: Maurice, link=no ; mfe, label= Mauritian Creole, Moris ), officially the Republic of Mauritius, is an island nation in the Indian Ocean about off the southeast coast of the African continent, east of Madagascar. It ...

* Ka'ena Point,

Oahu Oahu () ( Hawaiian: ''Oʻahu'' ()), also known as "The Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over two-thirds of the population of the U.S. state of Hawaii. The island of O� ...

* Mañagaha, Saipan,

CNMI The Northern Mariana Islands, officially the Commonwealth of the Northern Mariana Islands (CNMI; ch, Sankattan Siha Na Islas Mariånas; cal, Commonwealth Téél Falúw kka Efáng llól Marianas), is an unincorporated territory and commonwea ...

San Benedicto Island San Benedicto, formerly Isla de los Innocentes, 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 volcanic ...

Revillagigedo Islands The Revillagigedo Islands ( es, Islas Revillagigedo, ) 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 C ...

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 ...

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

Gallery

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

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

References

External links

BirdLife species factsheet
* California Bird Records Committee

*

USFWS The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...

, 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 ...