Great cormorant | |
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Nominate P. c. carbo, Northumberland, UK | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Suliformes |
Family: | Phalacrocoracidae |
Genus: | Phalacrocorax |
Species: | P. carbo |
Binomial name | |
Phalacrocorax carbo | |
Range of P. carbo Breeding Resident Passage Non-breeding | |
Synonyms | |
Pelecanus carboLinnaeus, 1758 |
The great cormorant (Phalacrocorax carbo), known as the black shag or kawau in New Zealand, formerly also known as the great black cormorant across the Northern Hemisphere, the black cormorant in Australia, and the large cormorant in India, is a widespread member of the cormorant family of seabirds. [2] It breeds in much of the Old World, Australasia, and the Atlantic coast of North America.
The great cormorant was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae under the binomial name Pelecanus carbo. [3] The great cormorant is now one of 12 species placed in the genus Phalacrocorax that was introduced in 1760 by the French zoologist Mathurin Jacques Brisson. [4] The genus name is Latinised Ancient Greek, from φαλακρός (phalakros, "bald") and κόραξ (korax, "raven"); the specific epithet carbo is Latin for "charcoal". [5]
Five subspecies are accepted. These are listed below with their breeding ranges. [4] Two additional species are very closely related, with genetic evidence suggesting they may be embedded within P. carbo; [6] they are shown in the list below for completeness.
Image | Scientific name | Common name | Distribution | Notes |
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Northumberland, UK | P. c. carbo (Linnaeus, 1758) | Atlantic cormorant | North Atlantic coasts from NW France, Britain, Ireland, western Norway, west Greenland, and east Canada to Maine (northeast USA), wintering south to north Florida; formerly also the Baltic Sea | Described by Linnaeus from Sweden in 1758, but extinct there soon after; subsequent recolonisation of the area has been by P. c. sinensis [7] |
Gojal, Gilgit-Baltistan, Pakistan | P. c. sinensis (Staunton, 1796) syn. P. c. subcormoranus(C. L. Brehm, 1824) | Continental cormorant large cormorant (India) | Transcontinental across Eurasia from inland western Europe to India and Sri Lanka, to northeast Russia, northeast China and the Korean Peninsula, south to Turkey, central Asia and north Mongolia; disjunctly central south Cambodia and south Vietnam, northeast Borneo | Now overlaps with P. c. carbo in SE England and elsewhere |
Osaka, Japan | P. c. hanedae Kuroda & Nm, 1925 | Japanese great cormorant | coastal and inland Japan, Hokkaido to Kyushu (north to south Japan) | Ecologically separated from P. capillatus, less strictly marine, often inland |
Souss-Massa National Park, Morocco | P. c. maroccanus Hartert, EJO, 1906 | Moroccan cormorant | coastal northwest Africa: Morocco to Mauretania | white neck and upper breast |
Victoria, Australia | P. c. novaehollandiae Stephens, 1826 | black cormorant (Australia) black shag (New Zealand), kawau (New Zealand, Māori name) [8] | inland and coastal Australasia: Australia, North Island, South Island, Stewart Island and Chatham Islands (east of South Island; New Zealand), Rennell Island (south Solomon Islands) and Grande Terre (New Caledonia) | Syntype in the collection of the Museum of New Zealand Te Papa Tongarewa. [9] |
Aichi prefecture, Japan | P. capillatus (Temminck & Schlegel, 1850) | Japanese cormorant | coastal Japan Hokkaido to Kyushu, Sakhalin, southeast Russia, Korea | Ecologically separated from P. c. hanedae, more strictly marine, rarely inland |
Lake Naivasha, Kenya | P. lucidus M. H. C. Lichtenstein, 1823 syn. P. carbo lucidus | White-breasted cormorant | sub-Saharan Africa | white neck and breast |
The great cormorant is a large black bird, but there is a wide variation in size in the species' wide range. Weight is reported to vary from 1.5 kg (3 lb 5 oz) [10] to 5.3 kg (11 lb 11 oz). [11] Males are typically larger and heavier than females, with the nominate race P. c. carbo averaging about 10% larger in linear measurements than the smaller subspecies P. c. sinensis. [12] The lightest average weights cited are in Germany (P. c. sinensis), where 36 males averaged 2.28 kg (5 lb 1⁄2 oz) and 17 females averaged 1.94 kg (4 lb 4+1⁄2 oz). [13] The highest come from Prince Edward Island in Canada (P. c. carbo), where 11 males averaged 3.68 kg (8 lb 2 oz) and 11 females averaged 2.94 kg (6 lb 7+1⁄2 oz). [14] [15] Length can vary from 70 to 102 cm (27+1⁄2 to 40 in) and wingspan from 121 to 160 cm (47+1⁄2 to 63 in). [15] [16] They are tied as the second largest extant species of cormorant after the flightless cormorant, with the Japanese cormorant averaging at a similar size. In bulk if not in linear dimensions, the blue-eyed shag species complex of the Southern Oceans are scarcely smaller at average. [13] It has a longish tail and yellow throat-patch. Adults have white filoplume patches on the thighs and on the head and upper neck in the breeding season. In European waters it can be distinguished from the common shag by its larger size, heavier build, thicker bill, lack of a crest and plumage without any green tinge. In eastern North America, it is similarly larger and bulkier than the double-crested cormorant; the latter species also has more yellow on the throat and bill and lacks the white thigh patches frequently seen on great cormorants. Great cormorants are mostly silent, but they make various guttural noises at their breeding colonies. [17]
The white filoplumes on the head in the breeding season vary with both the age of the bird, and the subspecies; older birds have more white filoplumes than younger birds, while nominate P. c. carbo tends to have fewer than P. c. sinensis, but there is much overlap. The extent of variation between individuals means it is not a very useful character for subspecies identification. [18]
A very rare variation of the great cormorant is caused by albinism. Albinos suffer from poor eyesight and/or hearing, thus it rarely manages to survive in the wild.[ citation needed ]
This is a very common and widespread bird species. It feeds on the sea, in estuaries, and on freshwater lakes and rivers. Northern birds migrate south and winter along any coast that is well-supplied with fish.[ citation needed ]
In Serbia, the cormorant lives in Vojvodina. However, after 1945 many artificial lakes were formed in Serbia; some of them became potential habitats for cormorants. Currently, on the Lake Ćelije, formed in 1980, there is a resident colony of cormorants, who nest there and are present throughout the year, except January–February 1985 and February 2012 when the lake surface was completely frozen.[ citation needed ]
The type subspecies, P. c. carbo, is found mainly in Atlantic waters and nearby inland areas: on western European coasts and east across the Palearctic to Siberia and to North Africa, the Faroe Islands, Iceland and Greenland; and on the eastern seaboard of North America. The subspecies P. c. novaehollandiae is found in Australian waters. [8]
The great cormorant often nests in colonies near wetlands, rivers, and sheltered inshore waters. Pairs will use the same nest site to breed year after year. It builds its nest, which is made from sticks, in trees, on the ledges of cliffs, and on the ground on rocky islands that are free of predators. [19]
This cormorant lays a clutch of three to five eggs that measure 63 by 41 millimetres (2+1⁄2 by 1+5⁄8 in) on average. The eggs are a pale blue or green, and sometimes have a white chalky layer covering them. These eggs are incubated for a period of about 28 to 31 days. [19]
The great cormorant feeds on fish caught through diving. [19] This bird feeds primarily on wrasses, but it also takes sand smelt, flathead and common soles. [20] The average weight of fish taken by great cormorants increased with decreasing air and water temperature. Cormorants consume all fish of appropriate size that they are able to catch in summer and noticeably select for larger, mostly torpedo-shaped fish in winter. Thus, the winter elevation of foraging efficiency described for cormorants by various researchers is due to capturing larger fish not due to capturing more fish. [21] In some freshwater systems, the losses of fish due to overwintering great cormorants were estimated to be up to 80 kg per ha each year (e.g. Vltava River, Czech Republic). [22]
This cormorant forages by diving and capturing its prey in its beak. [19] The duration of its dives is around 28 seconds, with the bird diving to depths of about 5.8 metres (19 ft 0 in). About 60% of dives are to the benthic zone and about 10% are to the pelagic zone, with the rest of the dives being to zones in between the two. [20] Studies suggest that their hearing has evolved for underwater usage, possibly aiding their detection of fish. [23] These adaptations also have a cost on their hearing ability in air which is of lowered sensitivity. [24]
Many fishermen see in the great cormorant a competitor for fish. Because of this, it was hunted nearly to extinction in the past. Due to conservation efforts, its numbers increased. At the moment, there are about 1.2 million birds in Europe (based on winter counts; late summer counts would show higher numbers). [25] Increasing populations have once again brought the cormorant into conflict with fisheries. [26] [27] For example, in Britain, where inland breeding was once uncommon, there are now increasing numbers of birds breeding inland, and many inland fish farms and fisheries now claim to be suffering high losses due to these birds. In the UK each year, some licences are issued to cull specified numbers of cormorants in order to help reduce predation; it is, however, still illegal to kill a bird without such a licence. [28]
Cormorant fishing is practised in China, Japan, and elsewhere around the globe. In this practice, fishermen tie a line around the throats of cormorants, tight enough to prevent swallowing the larger fish they catch, and deploy them from small boats. The cormorants catch fish without being able to fully swallow them, and the fishermen are able to retrieve the fish simply by forcing open the cormorants' mouths, apparently engaging the regurgitation reflex. [29]
In Norway, the cormorant is a traditional game bird. Each year approximately 10,000 cormorants are shot to be eaten. [30] In North Norway, cormorants are traditionally seen as semi-sacred.[ citation needed ] It is regarded as good luck to have cormorants gather near your village or settlement. An old legend states that for people who die far out at sea, whose bodies are never recovered, spend eternity on the island Utrøst – which can only occasionally be found by mortals. The inhabitants of Utrøst can only visit their homes in the shape of cormorants.[ citation needed ]
Phalacrocoracidae is a family of approximately 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed, but in 2021 the International Ornithologists' Union (IOU) adopted a consensus taxonomy of seven genera. The great cormorant and the common shag are the only two species of the family commonly encountered in Britain and Ireland and "cormorant" and "shag" appellations have been later assigned to different species in the family somewhat haphazardly.
The double-crested cormorant is a member of the cormorant family of water birds. It is found near rivers and lakes and in coastal areas and is widely distributed across North America, from the Aleutian Islands in Alaska down to Florida and Mexico. Measuring 70–90 cm (28–35 in) in length, it is entirely black except for a bare patch of orange-yellow facial skin and some extra plumage that it exhibits in the breeding season when it grows a double crest in which black feathers are mingled with white. Five subspecies are recognized. It mainly eats fish and hunts by swimming and diving. Its feathers, like all cormorants, are not waterproof, and it must dry them out after spending time in the water. Once threatened by the use of DDT, the numbers of this bird have increased markedly in recent years.
The pelagic cormorant, also known as Baird's cormorant or violet-green cormorant, is a small member of the cormorant family Phalacrocoracidae. Analogous to other smallish cormorants, it is also called the pelagic shag occasionally. This seabird lives along the coasts of the northern Pacific; during winter it can also be found in the open ocean. Pelagic cormorants have relatively short wings due to their need for economical movement underwater, and consequently have the highest flight costs of any bird.
The little pied cormorant, little shag or kawaupaka is a common species of Australasian waterbird, found around the coasts, islands, estuaries, and inland waters of Australia, New Guinea, New Zealand, Timor-Leste and Indonesia, and around the islands of the south-western Pacific and the subantarctic. It is a small short-billed cormorant usually black above and white below with a yellow bill and small crest, although a mostly black white-throated form predominates in New Zealand. Three subspecies are recognised. Until recently most authorities referred to this species as Phalacrocorax melanoleucos.
The European shag or common shag is a species of cormorant. It is the only member of the monotypic genus Gulosus. It breeds around the rocky coasts of western and southern Europe, southwest Asia and north Africa, mainly wintering in its breeding range except for the northernmost birds. In Britain this seabird is usually referred to as simply the shag. The scientific genus name derives from the Latin for glutton. The species name aristotelis commemorates the Greek philosopher Aristotle.
The Australian pied cormorant, also known as the pied cormorant, pied shag, or great pied cormorant, is a medium-sized member of the cormorant family. It is found around the coasts of Australasia. In New Zealand, it is usually known either as the pied shag or by its Māori name of kāruhiruhi. Older sources may refer to it as the "yellow-faced cormorant".
The Indian cormorant or Indian shag is a member of the cormorant family. It is found mainly along the inland waters of the Indian Subcontinent but extends west to Sind and east to Thailand and Cambodia. It is a gregarious species that can be easily distinguished from the similar sized little cormorant by its blue eyes, small head with a sloping forehead and a long narrow bill ending in a hooked tip.
The neotropic cormorant or olivaceous cormorant is a medium-sized cormorant found throughout the American tropics and subtropics, from the middle Rio Grande and the Gulf and Californian coasts of the United States south through Mexico and Central America to southern South America, where it is called by the indigenous name of biguá. It also breeds in the Bahamas, Cuba, and Trinidad. It can be found both on coasts and in inland waters. There are at least two subspecies: N. b. mexicanum from Nicaragua northwards and N. b. brasilianum further south. In Peru, the neotropic cormorant is used by the Uru people for fishing.
The little black cormorant is a member of the cormorant family of seabirds. It is common in smaller rivers and lakes throughout most areas of Australia and northern New Zealand, where it is known as the little black shag. It is around sixty centimetres long, and is all black with blue-green eyes.
The European perch, also known as the common perch, redfin perch, big-scaled redfin, English perch, Euro perch, Eurasian perch, Eurasian river perch, Hatch, poor man's rockfish or in Anglophone parts of Europe, simply the perch, is a predatory freshwater fish native to Europe and North Asia. It is the type species of the genus Perca.
The red-faced cormorant, red-faced shag or violet shag, is a bird species of the family Phalacrocoracidae.
The rock shag, also known as the Magellanic cormorant, is a marine cormorant found around the southernmost coasts of South America. Its breeding range is from around Valdivia, Chile, south to Cape Horn and Tierra del Fuego, and north to Punta Tombo in Argentina. In winter it is seen further north, with individuals reaching as far as Santiago, Chile on the west coast and Uruguay on the east. The birds also breed around the coasts of the Falkland Islands.
The white-breasted cormorant is a species of cormorant closely related to the widely distributed great cormorant. While debate persists over whether it constitutes a distinct species or a regional variant of the great cormorant, its distinguishing features include a white breast and a preference for freshwater habitats among its subpopulations. The species should not be confused with the smaller and morphologically distinct endemic South Australian black-faced cormorant, which occasionally shares the common name "white-breasted cormorant".
The New Zealand king shag, also known as the rough-faced shag, king shag or kawau tūī, is a rare bird endemic to New Zealand. Some taxonomic authorities, including the International Ornithologists' Union, place this species in the genus Leucocarbo. Others place it in the genus Phalacrocorax.
The imperial shag or imperial cormorant is a black and white cormorant native to southern South America, primarily in rocky coastal regions, but locally also at large inland lakes. Some taxonomic authorities, including the International Ornithologists' Union, place it in the genus Leucocarbo, others in the genus Phalacrocorax. It is also known as the blue-eyed shag, blue-eyed cormorant and by many other names, and is one of a larger group of cormorants called blue-eyed shags. The taxonomy is very complex, and several former subspecies are often considered separate species.
The red-legged cormorant, also known as the red-legged shag, red-footed cormorant, red-footed shag, Gaimard's cormorant and grey cormorant, is a species of cormorant resident to the coastline of South America. It is the only member of the genus Poikilocarbo. It is non-colonial unlike most seabirds. The red-legged cormorant has not been observed wing-spreading, which is unusual among cormorant species.
The Chatham Islands shag, also known as the Chatham shag, is a species of bird in the cormorant and shag family, Phalacrocoracidae. It is endemic to the Chatham Islands of New Zealand. For a long time the species was placed in the genus Phalacrocorax; today it is mostly placed with the other blue-eyed shags of New Zealand and Antarctica in the genus Leucocarbo. Its closest relative is the Otago shag of South Island.
The South Georgia shag, also known as the South Georgia cormorant, is a marine cormorant native to South Georgia and a few other subantarctic islands in the South Atlantic Ocean.
The Heard Island shag, or Heard Island cormorant, is a marine cormorant native to the Australian territory comprising the Heard and McDonald Islands in the Southern Ocean, which is about 4,100 km south-west of Perth, Western Australia.
The Antarctic shag, sometimes referred to as the imperial cormorant, king cormorant, imperial shag, blue-eyed shag or Antarctic cormorant, is the only species of the cormorant family found in the Antarctic. It is sometimes considered conspecific with the Imperial shag.
on the adoption of a European Cormorant Management Plan to minimise the increasing impact of cormorants on fish stocks, fishing and aquaculture
Around 10,000 adult Cormorants (of the 'Atlantic' carbo race) are hunted legally as game in Norway outside the breeding season.