The Christmas shearwater or ''aoū'' (''Puffinus nativitatis'') is a medium-sized

shearwater Shearwaters are medium-sized long-winged seabirds in the petrel 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 shearwa ...

of 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 ...

Central Pacific. It is a poorly known species due to its remote nesting habits, and it has not been extensively studied at sea either.Seto, N.W.H. (2001): Christmas Shearwater (''Puffinus nativitatis''). ''In:'' Poole, A. & Gill, F. (eds.): ''The Birds of North America'' 561.

Academy of Natural Sciences The Academy of Natural Sciences of Drexel University, formerly the Academy of Natural Sciences of Philadelphia, is the oldest natural science research institution and museum in the Americas. It was founded in 1812, by many of the leading natura ...

, Philadelphia, PA &

American Ornithologists' Union The American Ornithological Society (AOS) is an ornithological organization based in the United States. The society was formed in October 2016 by the merger of the American Ornithologists' Union (AOU) and the Cooper Ornithological Society. Its m ...

, Washington, D.C. (requires subscription) It is one member of a very ancient lineage of the small ''Puffinus'' species. Its only close living relative is the Galápagos shearwater (''P. subalaris'').

Taxonomy

The species was described and given its current

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

by the American naturalist Thomas Hale Streets in 1877. A genetic analysis using

mitochondrial A mitochondrion (; ) is an organelle found in the cells of most Eukaryotes, such as animals, plants and fungi. Mitochondria have a double membrane structure and use aerobic respiration to generate adenosine triphosphate (ATP), which is use ...

DNA has shown that the closest living relative is the Galápagos shearwater (''Puffinus subalaris'').

Description

The Christmas shearwater is a slender-bodied

, about 36 cm long, with a wingspan of around 75 cm, and weighs around 350 g. It has dark

plumage Plumage ( "feather") is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, ...

all over, generally blackish-grey with a rusty-brown tinge, slightly paler on the underside of the bird, and with some small edging of white under the chin and pale fringes to the upperwing coverts. It has brown-grey feet and a dark bill and eyes. Both sexes are alike, as are the young after

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 ...

Nestling Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight s ...

s are covered in dark grey

down feather The down of birds is a layer of fine feathers found under the tougher exterior feathers. Very young birds are clad only in down. Powder down is a specialized type of down found only in a few groups of birds. Down is a fine thermal insulator an ...

s.Seto (2001), Shirihai ''et al.'' (2009) The species closely resembles the

sooty Sooty is a British children's television media franchise created by Harry Corbett incorporating primarily television and stage shows. The franchise originated with his fictional glove puppet character introduced to television in 1955, with the ...

(''Puffinus griseus'') and

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 ...

s (''P. tenuirostris''), but has dark brown underwings and is smaller. The short tail of the Christmas shearwater does not appear blunt except when spread, but in flight usually tapers to a point, enhanced by the feet which protrude beyond the tail-tip. It often flies in a leisurely way like the related

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 also ...

, and thus can be mistaken for a petrel. In particular, it can appear similar to the extremely rare

Fiji petrel The Fiji petrel (''Pseudobulweria macgillivrayi''), also known as MacGillivray's petrel, is a small, dark gadfly petrel. The Fiji petrel was originally known from one immature specimen found in 1855 on Gau Island, Fiji by naturalist John MacGi ...

(''Pseudobulweria macgillivrayi''), a

gadfly petrel The gadfly petrels or ''Pterodroma'' are a genus of about 35 species of petrels, part of the seabird order Procellariiformes. The gadfly petrels are named for their speedy weaving flight, as if evading gadflies (horseflies). The flight action is ...

-like relative of the shearwaters. The two species share a similar

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...

and colouration, but the bulbous head and rather thin long bill – typical for shearwaters – distinguish ''P. nativitatis'' from the slim-headed thick-billed Fiji petrel.

Distribution and habitat

The Christmas shearwater nests on remote islands of the Central Pacific: the

Northwestern Hawaiian Islands The Northwestern Hawaiian Islands or Leeward Hawaiian Islands are a series of islands and atolls in the Hawaiian island chain located northwest (in some cases, far to the northwest) of the islands of Kauai and Niihau. Politically, they are all p ...

Tuamotu The Tuamotu Archipelago or the Tuamotu Islands (french: Îles Tuamotu, officially ) are a French Polynesian chain of just under 80 islands and atolls in the southern Pacific Ocean. They constitute the largest chain of atolls in the world, extendin ...

, the

Marshall Islands The Marshall Islands ( mh, Ṃajeḷ), officially the Republic of the Marshall Islands ( mh, Aolepān Aorōkin Ṃajeḷ),'' () is an independent island country and microstate near the Equator in the Pacific Ocean, slightly west of the Internati ...

Kiritimati Kiritimati (also known as Christmas Island) is a Pacific Ocean atoll in the northern Line Islands. It is part of the Republic of Kiribati. The name is derived from the English word "Christmas" written in Gilbertese according to its phonology, ...

(for which the species is named) and Sala-y-Gómez. It has become

locally extinct Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinct ...

on a number of islands, including

Wake Island Wake Island ( mh, Ānen Kio, translation=island of the kio flower; also known as Wake Atoll) is a coral atoll in the western Pacific Ocean in the northeastern area of the Micronesia subregion, east of Guam, west of Honolulu, southeast of To ...

. Outside of the breeding season it ranges across the Pacific, having been recorded off the coast of Mexico and Guatemala in the east, and

Bonin Islands The Bonin Islands, also known as the , are an archipelago of over 30 subtropical and tropical islands, some directly south of Tokyo, Japan and northwest of Guam. The name "Bonin Islands" comes from the Japanese word ''bunin'' (an archaic readi ...

in the west. Further south it is rare, having been recorded off

Fiji Fiji ( , ,; fj, Viti, ; Fiji Hindi: फ़िजी, ''Fijī''), officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists ...

only twice (one time in early to mid-May).

Behaviour

Diet and feeding

Like its relatives it feeds at sea, predominantly on

squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...

, and fish, mostly

flying fish The Exocoetidae are a family of marine fish in the order Beloniformes class Actinopterygii, known colloquially as flying fish or flying cod. About 64 species are grouped in seven to nine genera. While they cannot fly in the same way a bird do ...

(Exocoetidae) and

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 Lati ...

(Mullidae). It is highly

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 wa ...

and is dependent on predatory fish such as

tuna A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max length: ...

driving prey to the surface. As mentioned above, it does not only have the dramatic stiff-winged "shearing" (

dynamic soaring Dynamic soaring is a flying technique used to gain energy by repeatedly crossing the boundary between air masses of different velocity. Such zones of wind gradient are generally found close to obstacles and close to the surface, so the technique is ...

) flight technique which gave the shearwaters their common name. In addition to it, it may use the

plesiomorph In phylogenetics, a plesiomorphy ("near form") and symplesiomorphy are synonyms for an ancestral character shared by all members of a clade, which does not distinguish the clade from other clades. Plesiomorphy, symplesiomorphy, apomorphy, and ...

ic flight technique of

petrel Petrels are tube-nosed seabirds in the bird order Procellariiformes. Description The common name does not indicate relationship beyond that point, as "petrels" occur in three of the four families within that group (all except the albatross f ...

s and similar

, moving about with slow, leisurely wingbeats.

Breeding

The Christmas shearwater nests on sandy islands with good cover. It nests on the surface, underneath dense cover (such as naupakas, ''Scaevola''), or under rock outcroppings. It lays one white

egg An egg is an organic vessel grown by an animal to carry a possibly fertilized egg cell (a zygote) and to incubate from it an embryo within the egg until the embryo has become an animal fetus that can survive on its own, at which point the a ...

, the timing of laying varying from island to island, on some islands breeding throughout the year. The egg is incubated for around 50 days. The time taken to

fledge 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 ...

varies depending on the

season A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region. On Earth, seasons are the result of the axial parallelism of Earth's tilted orbit around the Sun. In temperate and pol ...

, ranging from 60 to 100 days.

Status and conservation

Although few specific studies have been conducted on the Christmas shearwaters, petrels and shearwaters are threatened worldwide by

fishing Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from stocked bodies of water such as ponds, canals, park wetlands and reservoirs. Fishing techniques inclu ...

, ingestion of

plastic waste Plastic pollution is the accumulation of plastic objects and particles (e.g. plastic bottles, bags and microbeads) in the Earth's environment that adversely affects humans, wildlife and their habitat. Plastics that act as pollutants are catego ...

, and habitat degradation. For example, on

Laysan Island Laysan (; haw, italics=no, Kauō ), located northwest of Honolulu at , is one of the Northwestern Hawaiian Islands. It comprises one land mass of , about in size. It is an atoll of sorts, although the land completely surrounds a shallow ...

the introduced

rabbit Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit speci ...

s degraded the scrub cover, leaving adults, chicks and eggs vulnerable to overheating, and introduced

black rat The black rat (''Rattus rattus''), also known as the roof rat, ship rat, or house rat, is a common long-tailed rodent of the stereotypical rat genus ''Rattus'', in the subfamily Murinae. It likely originated in the Indian subcontinent, but is n ...

s took eggs and chicks. In 1985, the population on Sala-y-Gómez, a nature

sanctuary A sanctuary, in its original meaning, is a sacred place, such as a shrine. By the use of such places as a haven, by extension the term has come to be used for any place of safety. This secondary use can be categorized into human sanctuary, a saf ...

, was estimated at 5,000. With its wide range and considerable numbers, the Christmas shearwater is considered a species of

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

.Seto (2001), BLI (2009)

Footnotes

References

* Austin, Jeremy J. (1996): Molecular Phylogenetics of ''Puffinus'' Shearwaters: Preliminary Evidence from Mitochondrial Cytochrome ''b'' Gene Sequences. '' Mol. Phylogenet. Evol.'' 6(1): 77–88. (HTML abstract) * Seto, N.W.H. (2001): Christmas Shearwater (''Puffinus nativitatis''). ''In:'' Poole, A. & Gill, F. (eds.): ''The Birds of North America'' 561.

, Philadelphia, PA &

, Washington, D.C. (requires subscription) * Shirihai, Hadoram; Pym, Tony; Kretzschmar, Jörg; Moce, Kolinio; Taukei, Amania & Watling, Dick (2009): First observations of Fiji Petrel ''Pseudobulweria macgillivrayi'' at sea: off Gau Island, Fiji, in May 2009. '' Bull. B.O.C.'' 129(3): 129–148
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{{Taxonbar, from=Q1269689

Christmas shearwater The Christmas shearwater or ''aoū'' (''Puffinus nativitatis'') is a medium-sized shearwater of the tropical Central Pacific. It is a poorly known species due to its remote nesting habits, and it has not been extensively studied at sea either. ...

Birds of the Pacific Ocean