Snow Petrel

Snow Petrel

Overview
The Snow Petrel is the only member of the genus Pagodroma. It is one of only three birds that breed exclusively in Antarctica and has been seen at the South Pole. It has the most southerly breeding distribution of any bird.

The Snow Petrel is the only member of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Pagodroma, and a member of the sub-family Fulmarine petrel
Fulmarine petrel
The fulmarine petrels or fulmar-petrels are a distinct group of petrels within the procellariidae family. They are the most variable of the four groups within the Procellariidae, differing greatly in size and biology. They do have, however, have a unifying feature, their skull, and in particular...

s. They in turn are all members of the Procellariidae
Procellariidae
The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the prions, and the shearwaters. This family is part of the bird order Procellariiformes , which also includes the albatrosses, the storm-petrels, and the diving petrels.The procellariids are...

 family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

, and the Procellariiformes
Procellariiformes
Procellariiformes is an order of seabirds that comprises four families: the albatrosses, petrels and shearwaters, storm petrels, and diving petrels...

 order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

. They all share certain identifying features.
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Encyclopedia
The Snow Petrel is the only member of the genus Pagodroma. It is one of only three birds that breed exclusively in Antarctica and has been seen at the South Pole. It has the most southerly breeding distribution of any bird.

Taxonomy


The Snow Petrel is the only member of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Pagodroma, and a member of the sub-family Fulmarine petrel
Fulmarine petrel
The fulmarine petrels or fulmar-petrels are a distinct group of petrels within the procellariidae family. They are the most variable of the four groups within the Procellariidae, differing greatly in size and biology. They do have, however, have a unifying feature, their skull, and in particular...

s. They in turn are all members of the Procellariidae
Procellariidae
The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the prions, and the shearwaters. This family is part of the bird order Procellariiformes , which also includes the albatrosses, the storm-petrels, and the diving petrels.The procellariids are...

 family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

, and the Procellariiformes
Procellariiformes
Procellariiformes is an order of seabirds that comprises four families: the albatrosses, petrels and shearwaters, storm petrels, and diving petrels...

 order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

. They all share certain identifying features. First, they have nasal passages that attach to the upper bill called naricorns. Although the nostrils on the Albatross are on the sides of the bill. The bills of Procellariiformes are also unique in that they are split into between 7 and 9 horny plates. They produce a stomach oil made up of wax ester
Wax ester
An ester of a fatty acid and a long-chain alcohol. These oils have similar properties as triglycerides, but are indigestible. They are found in some fish such as orange roughy, oilfish, escolar, black oreo, smooth oreo and other deep water fish. They are also present in marine copepods. Wax...

s and triglycerides that is stored in the proventriculus
Proventriculus
The proventriculus is part of the digestive system of birds, invertebrates and insects.-Birds:The proventriculus is a standard part of avian anatomy...

. This is used against predators as well as an energy rich food source for chicks and for the adults during their long flights. Finally, they also have a salt gland that is situated above the nasal passage and helps desalinate their bodies, due to the high amount of ocean water that they imbibe. It excretes a high saline solution from their nose.

Sub-species


There are two subspecies,
  • Pagodroma nivea confusa breeds on the South Sandwich Islands and Géologie Archipelago
    Geologie Archipelago
    Geologie Archipelago is a small archipelago of rocky islands and rocks close north of Cape Geodesie and Astrolabe Glacier Tongue, extending from Helene Island on the west to Dumoulin Islands on the east. The French expedition under Captain Jules Dumont d'Urville landed on Debarquement Rock in the...

    .
  • Pagodroma nivea nivea breeds on the Antarctic Peninsula
    Antarctic Peninsula
    The Antarctic Peninsula is the northernmost part of the mainland of Antarctica. It extends from a line between Cape Adams and a point on the mainland south of Eklund Islands....

    , South Georgia Islands, and other islands of the Scotia Archipelago.

They differ in size, and the greater form has a stouter, larger beak.

Nomenclature



The issue of taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 and nomenclature for this species is complex, and represents an example of many of the unusual problems which arise out of the varied use of the terminiology.

The snow petrel was first named Procellaria nivea by Georg Forster
Georg Forster
Johann Georg Adam Forster was a German naturalist, ethnologist, travel writer, journalist, and revolutionary. At an early age, he accompanied his father on several scientific expeditions, including James Cook's second voyage to the Pacific...

, during Captain James Cook's third voyage in 1777 as . As Forster's mention of the petrel was only an observation, the authority of the name fell to Gmelin
Johann Friedrich Gmelin
Johann Friedrich Gmelin was a German naturalist, botanist, entomologist, herpetologist and malacologist.- Education :Johann Friedrich Gmelin was born as the eldest son of Philipp Friedrich Gmelin in 1748 in Tübingen...

, in his
Systema Naturae
Systema Naturae
The book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...

. Incidentally, a skin was procured by Cook, who noted this in his own account (1777). It was J. R. Forster who painted a picture of it, and made measurements as well, but only the latter were published, posthumously, by M. H. K. Lichtenstein in 1844. While Gmelin was recognized as the authority for P. nivea until the early twentieth century, the evidence has allowed for Forster to be construed as such, as he had created the name. In addition, Latham (1785) had described the type, which was in the Leverian Museum, but did not invoke Forster's scientific name for it.

Charles Lucien Bonaparte
Charles Lucien Bonaparte
Charles Lucien Jules Laurent Bonaparte, 2nd Prince of Canino and Musignano was a French naturalist and ornithologist.-Biography:...

, in his
Conspectus Generum Avium, volume II (1857), designated two subspecific binomial terms with no further descriptions to them: Pagodroma major and Pagodroma minor. Contrary to Mathews in Novitates Zoologicae (1934), the two names do not represent alternative, new names for P. nivea, but are subspecies, as well as nomen nudum, on account of their being listed similar to how other subspecies Bonaparte listed in the Conspectus. It was also Bonaparte who created the generic name Pagodroma, in the Paris academic journal Compte Rendus.. (1856). James Francis Stephens
James Francis Stephens
James Francis Stephens was an English entomologist.-Biography:Stephens was born in Shoreham-by-Sea and studied at Christ's Hospital.He was employed in the Admiralty office, Somerset House, from 1807 to 1845...

 (
General Zoology, 1826) equated Pagodroma nivea in the genus Daption, Heinrich Reichenbach (Avium Systema Naturale, 1852) included it in the genus Thalassoica, and George Robert Gray
George Robert Gray
George Robert Gray FRS was an English zoologist and author, and head of the ornithological section of the British Museum, now the Natural History Museum, in London for forty-one years...

 (
Hand-list of the Birds, 1871) included it in the genus Fulmarus.

Hermann Schlegel
Hermann Schlegel
Hermann Schlegel was a German ornithologist and herpetologist.-Early life and education:Schlegel was born at Altenburg, the son of a brassfounder. His father collected butterflies, which stimulated Schlegel's interest in natural history...

, in his treatise on birds in the Leiden Museum
Naturalis
Naturalis is the national natural history museum of the Netherlands, based in Leiden. It originated from the merger of the Rijksmuseum van Natuurlijke Historie and the Rijksmuseum van Geologie en Mineralogie in 1984. In 1986 it was decided that the museum had to become a public museum and a new...

 in
Mus. Pay-Bas (1863), designated two forms of the snow petrel for the first time. He had believed, erroneously, that the Cook expedition specimen represented the greater snow petrel, and designated it as Pagodroma nivea, incorporating P. major (Bonaparte) as a synonym of it. He thus redundantly described Procellaria nivea minor, also extracted from Bonaparte's nomen nudum, as the lesser form. With the measurements provided by Lichtenstein taken from J. R. Forsters' manuscript, it was already clear by this time that nivea represented the lesser snow petrel.

This matter was further clarified by Gregory Mathews
Gregory Mathews
Gregory Macalister Mathews CBE was an Australian amateur ornithologist.Mathews made his fortune in mining shares, and moved to England around 1900....

, who in Birds of Australia, volume 2 (1912), described the greater form as Pagodroma confusa. However, Mathews did not designate a type for this, and it was Ernst Hartert
Ernst Hartert
Ernst Johann Otto Hartert was a German ornithologist. Hartert was born in Hamburg. He was employed by Lionel Walter Rothschild as ornithological curator of his private museum at Tring from 1892 to 1929....

 (Novitates Zoologicae, 1926) who identified P. confusa with lectotypes in the British Museum
British Museum
The British Museum is a museum of human history and culture in London. Its collections, which number more than seven million objects, are amongst the largest and most comprehensive in the world and originate from all continents, illustrating and documenting the story of human culture from its...

, (Tring
Tring
Tring is a small market town and also a civil parish in the Chiltern Hills in Hertfordshire, England. Situated north-west of London and linked to London by the old Roman road of Akeman Street, by the modern A41, by the Grand Union Canal and by rail lines to Euston Station, Tring is now largely a...

). From that time debate has persisted as to whether the snow petrel represents one monotypic species, one species with two subspecies, or two different species. In addition, J. Prevost (Oiseaux, 1969) identified Pagodroma nivea major to the greater snow petrel, thus rendering valid the nomen nudum of Bonaparte.

In the 1850s the "Rattlesnake" expedition procured specimens of the snow petrel from the South Georgia/Falklands Is. region, near South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. A German Antarctic exploring expedition, 1882–83, also obtained skins, and opinion had emerged that the petrel populations there were unique from P. nivea. What distinguished the skins were the black shafts to the remiges, or flight feathers. Heinrich Pagenstecher in 1885 proposed the binomial name for a subspecies, Pagodroma novegeorgica (Jahrbuch Wiss. Hamburg II). The publication of this name was overlooked by English-speaking naturalists, and a similar account by Karl von der Steinen (1890) which had informally dropped the name novegeorgica, was not; this later account came to represent the scientific authority for South Georgia petrels. Gregory Mathews, in his Birds, designated the type from the "Rattlesnake" expedition to Steinen's "name". Later adding to the confusion, he assumed that the name novegeorgica could not be used for South Georgia petrels: Steinen's use of the term was not valid in a taxonomic sense, and this same term had been reinforced by its usage within the synopses of other, previous works. Thus, he created a nomen novum for the type he had designated in Birds, as Pagodroma nivea falklandica (Bulletin of the British Orn. Club, 1926). Eventually, Hellmayr and Conover (Museum of Nat. Hist. Publications, Chicago; 1949) unravelled the matter by recognizing Pagenstecher as the authority for novegeorgica, and omitting reference to Steinen.

In the decade following the United States Exploring Expedition
United States Exploring Expedition
The United States Exploring Expedition was an exploring and surveying expedition of the Pacific Ocean and surrounding lands conducted by the United States from 1838 to 1842. The original appointed commanding officer was Commodore Thomas ap Catesby Jones. The voyage was authorized by Congress in...

, Titian Ramsay Peale (1848) wrote an account of the bird and mammal specimens collected, including the description of an atypical snow petrel that was completely white—even the loral area behind the eye. The name Procellaria candida was published as an alternative synonym for the entry of Procellaria nivea. Mathews (1912) recognized Pagodroma nivea candida as a subspecies, taken from Peale's name. However, with the prevailing attitude at the time that names used in synonymy could not be used to identify forms, he later felt that P. n. candida could not be used and then amended this by creating the name Pagodroma nivea pealei. (Bulletin of the British Orn. Club, 1928). Mathews also described the subspecies Pagodroma nivea alba (Bulletin of the British Orn. Club, 1928) for the type he designated in his book, Birds of Norfolk and Lord Howe Islands (1928); the latter had also included information on the avifauna of the Australasian quadrant of Antarctica.

In Du Cane Godman
Frederick DuCane Godman
Frederick DuCane Godman D.C.L., F.R.S., F.L.S., F.G.S., F.R.G.S., F.E.S., F.Z.S., M.R.I., F.R.H.S., M.B.O.U. was an English lepidopterist, entomologist and ornithologist....

's, (Monograph of the Petrels, fasc. 4, 1909), it was figured in an illustration by John Gerrard Keulemans
John Gerrard Keulemans
Johannes Gerardus Keulemans was a Dutch bird illustrator.-Biography and Work:...

 (pl. 73).

Etymology


The word Petrel is derived from St. Peter and the story of his walking on water. This is in reference to the Petrels habit of appearing to run on the water to take off. Also, Pagodroma can be broken down as follows, pagos is Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 for ice and dromos for a running course. Nivea is derived from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 and either nix or nivis meaning snow or niveus meaning snowy. The snow reference is probably meant for its white color.

Description


The Snow Petrel, Pagodroma nivea, is a small, pure white fulmarine petrel
Fulmarine petrel
The fulmarine petrels or fulmar-petrels are a distinct group of petrels within the procellariidae family. They are the most variable of the four groups within the Procellariidae, differing greatly in size and biology. They do have, however, have a unifying feature, their skull, and in particular...

 with black underdown, coal-black eyes, small black bill and bluish gray feet. Body length is 36 to 41 cm (14.2 to 16.1 in) and the wingspan is 76 to 79 cm (29.9 to 31.1 in). Flight is more fluttering than most petrels. They are known to live 14 to 20 years.

Breeding


Breeding occurs in colonies
Bird colony
A bird colony is a large congregation of individuals of one or more species of bird that nest or roost in close proximity at a particular location. Many kinds of birds are known to congregate in groups of varying size; a congregation of nesting birds is called a breeding colony...

 on the Antarctic Peninsula
Antarctic Peninsula
The Antarctic Peninsula is the northernmost part of the mainland of Antarctica. It extends from a line between Cape Adams and a point on the mainland south of Eklund Islands....

, and various Antarctic
Antarctic
The Antarctic is the region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica and the ice shelves, waters and island territories in the Southern Ocean situated south of the Antarctic Convergence...

 islands. Nesting is colonial in small to large colonies on cliffs, usually near the sea, but also inland. Some birds remain at the colony all year, but the main influx at colonies is from the mid-September until early November. Nests are simple pebble-lined scrapes usually in a deep rock crevices with overhanging protection. One white egg
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...

 is laid in late November to mid-December. The egg is incubated
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...

 for 41 to 49 days and the chick is brooded for 8 days. They fledge
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...

 7 weeks later in late February to mid-May. Colonies are also the sites of cleaning areas where Snow Petrels, far from the sea, bathe in snow.

Snow petrel partners are faithful for life (around 20 years).

Feeding


Snow Petrels feed mainly on fish, some cephalopods, mollusks and krill
Krill
Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...

 as well as carrion
Carrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...

. During the winter they disperse to the pack ice, ice floes and the open sea. Flocks are characteristically seen sitting on icebergs. Only very rarely are they observed north of the pack ice.

Conservation


The Snow Petrel has an occurrence range of 35900000 km² (13,861,067 sq mi), and an estimated population of 4,000,000 adult birds. Based on these numbers the IUCN has classified this bird as Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...

.