Phalacrocoracidae: Cormorants and Shags
The Phalacrocoracidae family of birds is represented by 38 species of cormorants and shags. Several different classifications of the family have been proposed recently, but in the one most commonly used, all but three species are placed in a single genus Phalacrocorax, the exceptions being the Galapagos' Flightless Cormorant, the Kerguelen Shag and the Imperial Shag.
Names
There is no consistent distinction between cormorants and shags. The names "cormorant" and "shag" were originally the common names of the two species of the family found in Great Britain, Phalacrocorax carbo (now referred to by ornithologists as the Great Cormorant) and P. aristotelis (the Common Shag). "Shag" refers to the bird's crest, which the British forms of the Great Cormorant lack. As other species were discovered by English-speaking sailors and explorers elsewhere in the world, some were called cormorants and some shags, depending on whether they had crests or not. Sometimes the same species is called a cormorant in one part of the world and a shag in another, e.g. the Great Cormorant is called the Black Shag in New Zealand (the birds found in Australasia have a crest that is absent in European members of the species). Some modern classifications of the family have divided it into two genera and have tried to attach the name "Cormorant" to one and "Shag" to the other, but this flies in the face of common usage and has not been widely adopted.
The scientific genus name is latinized Ancient Greek, from phalakros (bald) and korax (raven). "Cormorant" is a contraction derived from Latin corvus marinus, "sea raven". Indeed, "sea raven" or analogous terms were the usual terms for cormorants in Germanic languages until after the Middle Ages, and the erroneous belief that these birds were related to ravens lasted at least to the 16th century:
"...le bec semblable à celuy d'un cormaran, ou autre corbeau." (...the beak similar to that of a cormorant or other corvids."; Thevet, 1558).
Characteristics
Cormorants and shags are medium-to-large seabirds. The majority, including all Northern Hemisphere species, have mainly dark plumage, but some Southern Hemisphere species are black and white, and a few (e.g. the Spotted Shag of New Zealand) are quite colourful. Many species have areas of coloured skin on the face (the lores and the gular skin) which can be bright blue, orange, red or yellow, typically becoming more brightly coloured in the breeding season. The bill is long, thin, and sharply hooked. Their feet are four-toed and webbed, a distinguishing feature among the Pelecaniformes order.
They are coastal rather than oceanic birds, and some have colonised inland waters. They range around the world, except for the central Pacific islands.
All are fish-eaters, dining on small eels, fish, and even water snakes. They dive from the surface, though many species make a characteristic half-jump as they dive, presumably to give themselves a more streamlined entry into the water. Under water they propel themselves with their feet. Some cormorant species have been found, using depth gauges, to dive to depths of as much as 45 metres.
After fishing, cormorants go ashore, and are frequently seen holding their wings out in the sun; it is assumed that this is to dry them. Unusually for a water bird, their feathers are not waterproofed. This may help them dive quickly, since their feathers do not retain air bubbles.
Cormorants are colonial nesters, using trees, rocky islets, or cliffs. The eggs are a chalky-blue colour. There is usually one brood a year. The young are fed through regurgitation. They typically have deep, ungainly bills which make it obvious that they are related to pelicans.
Species
- Genus Phalacrocorax
- Brandt's Cormorant, Phalacrocorax penicillatus
- Double-crested Cormorant or White-crested Cormorant, Phalacrocorax auritus
- Great Cormorant, Phalacrocorax carbo
- Neotropic Cormorant, Phalacrocorax brasilianus
- Olivaceous Cormorant or Mexican Cormorant, Phalacrocorax olivaceus: The Olivaceous Cormorant is a medium-sized member of the cormorant family found in tropical and near tropical regions of North and Central America, from the south-central United States (chiefly Texas and Louisiana) south to Nicaragua. It can be found both at coasts and inland. It is also found in Cuba and the Bahamas. From Costa Rica southwards it is replaced by the Neotropic Cormorant Phalacrocorax brasilianus, and some authors treat it as a subspecies of that form, classifying it as P. b. mexicanus. The Olivaceous Cormorant is an all black bird except for a tuft of white feathers above the ear and scattered white filoplumes on the side of the head and the neck, only seen in the breeding season. The lores (the regions between the eyes and bill on the side of a bird's head) and gular skin become orange or dark yellow in breeding birds. The upper wings are somewhat greyer than the rest of the body. Adults males weigh from 1.1 to 1.5 Kg, adult females 50 to 100 grams less. Information about their prey is sparse, but inland birds seem to feed on small, abundant fish in ponds and sheltered inlets, less than 10 cm in length, with an individual weight of a gram or two, such as Poecilia spp. especially the sailfin molly Poecilia latipinna. The birds' dives are correspondingly brief, between 5 and 15 seconds. Olivaceous cormorants nest in small colonies, building stick nests a few metres above ground (or water) in bushes or trees. Most pairs lay 3 eggs, but the mean number hatched is less than 2.
- Pelagic Cormorant or Baird's Cormorant, Phalacrocorax pelagicus
- Red-faced Cormorant, Phalacrocorax urile
- Guanay Cormorant , Phalacrocorax bougainvillii (off Peru, guano collected from nesting colonies of this bird is used to produce internationally traded commercial fertilizer)
- Little Black Cormorant, Phalacrocorax sulcirostris
- Indian Cormorant, Phalacrocorax fuscicollis
- Cape Cormorant, Phalacrocorax capensis
- Socotran Cormorant, Phalacrocorax nigrogularis : The Socotra Cormorant is endemic to the Persian Gulf and the south-east coast of the Arabian Peninsula. It is also sometimes known as the Socotran cormorant or, more rarely, as the Socotra shag. Individuals occasionally migrate as far west as the Red Sea coast, but although the first specimen recorded was found on Socotra island, giving the bird its name, it is unlikely that it breeds there. The Socotra Cormorant is an almost entirely black bird. In breeding condition, its forecrown has a purplish gloss and its upperparts have a slaty-green tinge, there are a few white plumes around the eye and neck and a few white streaks at the rump. Its legs and feet are black and its gular skin blackish. All these deviations from pure black are less marked outside the breeding season. Wing breadths of 275-310 cm have been recorded. There is little information on this species' foraging or diet. Like all cormorants its dives for its food. Older reports suggest that it can stay submerged for up to 3 minutes, which is high for a cormorant and suggests that it would be capable of deep diving. However there are also reports of forgaging in flocks, and this is more usually seen in cormorants that feed in mid water. The birds are highly gregarious, with roosting flocks of 250,000 having been reported, and flocks of up to 25,000 at sea. Some authors (e.g. Johnsgaard) place this species, along with a number of other related cormorants, in genus Leucocarbo. Since 2000, this species has been listed as Vulnerable on the IUCN Red List, on the grounds of its small range (only a small number of breeding locations are known, with estimates ranging from 9-13). Its number are suspected to be undergoing a continuous and rapid decline because of human development near its nesting colonies; a recent estimate of the world population put it at about half a million. The only nesting colony remaining in the Gulf is one of about 30,000 birds on the Bahraini Hawar Islands off the coast of Oman, and this is a Ramsar listed site. The birds may also be affected by oil pollution at sea. During the First Gulf War images of badly oiled cormorants from the Gulf were regularly shown in the western media, and although the Great Cormorant is also found in the Gulf, it is likely that many of these were Socotra cormorants. The Socotra Cormorant is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.
- Wahlberg's Cormorant or Bank Cormorant, Phalacrocorax neglectus: The Bank Cormorant is a medium-sized cormorant that is endemic to Namibia and the western seaboard of South Africa, living in and around coastal waters; it is rarely recorded more than 15Km offshore. The Bank Cormorant is a heavy-bodied bird, roughly 75cm in length. It is generally black in appearance with a bronze sheen, though the wings are a dark brown rather than a true black. Adults have a small crest on their heads, and normally have a white rump. A prime food for these birds is the Cape Rock Lobster Jasus lalandii, and their feeding distribution closely matches the kelp beds where these lobsters live, though the birds will also take a variety of other crustacean and fish prey, notably Pacific Goby Sufflogobius bibarbatus. The birds may breed at any time of the year, laying two or three chalky-white eggs in a nest constructed from seaweed and guano. Numbers of these birds have been declining sharply in recent decades, partly because of commercial fishing for Pacific Goby, partly because of increasing human disturbance, and partly because numbers of Kelp Gulls have been increasing because of human provisioning, and the gulls are active predators on the cormorant eggs and chicks. The world population is probably now around 4000 birds. The most important population centres are in Mercury Island and Ichaboe Island in Namibia.
- Temminck's Cormorant or Japanese Cormorant, Phalacrocorax capillatus: The Japanese Cormorant is native to East Asia, from Taiwan north through Korea and Japan to the Russian Far East. The Japanese Cormorant has a black body, with a white throat and cheek, and a partially yellow bill. It is one of the species of cormorant that has been domesticated by fishermen, in a tradition known in Japan as ukai.
- Common Shag aka European Shags, Phalacrocorax aristotelis
- Rock Shag, Phalacrocorax magellanicus
- Long-tailed Cormorant, Phalacrocorax africanus
- White-breasted Cormorant, Phalacrocorax lucidus
- Crowned Cormorant, Phalacrocorax coronatus The Crowned Cormorant is a small cormorant that is endemic to Namibia and the western seaboard of South Africa. It is a marine species, found on islands, coasts and estuaries usually within 10 km of land. It builds a nest from kelp, sticks, bones and lines it with kelp or feathers. The nest is usually in an elevated position such as a rocks, trees or man-made structures, but may be built on the ground. The Crowned Cormorant is 50-55 cm in length. Adults are black with a small crest on the head and a red face patch. Young birds are dark brown above, paler brown below, and lack the crest. They can be distinguished from immature Reed Cormorants by their darker underparts and shorter tail. Crowned Cormorants feed on slow-moving fish and invertebrates, which they forage for in shallow coastal waters and among kelp beds. The population appears to be between 2500 and 2900 breeding pairs. Ringing recoveries show that juveniles may disperse up to 277 km from their nests, and adults move between breeding sites over 500 km apart. Threats to the species include predation of eggs and chicks by Kelp Gulls and White Pelicans, human disturbance, oiling, and commercial fishing activities, including entanglement in marine debris and fishing gear
- Little Cormorant, Phalacrocorax niger
- Pygmy Cormorant, Phalacrocorax pygmaeus
- Pitt Cormorant or Featherstone's Shag Phalacrocorax featherstoni: Endemic to New Zealand. Its natural habitats are open seas and rocky shores. It is threatened by habitat loss.
- Pied Cormorant or Yellow-faced Cormorant, Phalacrocorax varius
- King Shag, also known as New Zealand King Shag or Rough-faced Shag Phalacrocorax carunculatus: The King Shag is a rare bird endemic to New Zealand. It is a large (76cm long, 2.5 kg in weight) black and white cormorant with pink feet. White patches on the wings appear as bars when the wings are folded. Yellow-orange swellings (caruncules) are found above the base of the bill. The grey gular pouch is reddish in the breeding season. A blue eye-ring indicates its kinship with the other blue-eyed shags. King Shags live in the coastal waters of the Marlborough Sounds. They can be seen from the Cook Strait Ferry in Queen Charlotte Sound opposite the beginning of the Troy Channel
- Black-faced Cormorant, Phalacrocorax fuscescens
- Spectacled Cormorant or Pallas's Cormorant Phalacrocorax perspicillatus (extinct): The Spectacled Cormorant is an extinct marine bird of the cormorant family of seabirds that inhabited Bering Island and possibly other places in the Komandorski Islands. A presumed prehistoric record from Amchitka Island, Alaska (Siegel-Causey et al., 1991), is based on misidentification of Double-crested Cormorant remains (Olson, 2005). The species was first identified by Georg Steller in 1741 on Vitus Bering's disastrous second Kamchatka expedition. He described the bird as large, clumsy and almost flightless - though it was probably rather reluctant to fly than physically unable -, and wrote "they weighed 12 – 14 pounds, so that one single bird was sufficient for three starving men." Apart from the fact that it fed on fish, almost nothing else is known about this bird. The population declined quickly after further visitors to the area started collecting the birds for food and feathers, and their reports of profitable whaling grounds and large populations of Arctic Foxes and other animals with valuable pelts led to a massive influx of whalers and fur traders into the region; the last birds were reported to have lived around 1850 on Ariy Rock (Russian: Арий Камень[2]) islet, off the northwestern tip of Bering Island
- Red-footed Shag, Phalacrocorax gaimardi: Found in Argentina, Chile, Falkland Islands, and Peru. Its natural habitats are shallow seas and rocky shores. It is threatened by habitat loss.
Spotted Shag Phalacrocorax punctatus
- Imperial Shag or Blue-eyed Shag, Phalacrocorax atriceps
- White-bellied Shag, Phalacrocorax atriceps albiventer
- Kerguelen Shag, Phalacrocorax verrucosus
- Little Pied Cormorant, Phalacrocorax melanoleucos
- Stewart Island Shag, Phalacrocorax chalconotus
- Chatham Shag, Phalacrocorax onslowi: Endemic to New Zealand. Its natural habitats are open seas and rocky shores. It is threatened by habitat loss.
- Auckland Shag, Phalacrocorax colensoi
- Campbell Shag, Phalacrocorax campbelli: Endemic to New Zealand. Its natural habitats are open seas and rocky shores.
- Bounty Shag, Phalacrocorax ranfurlyi : Endemic to New Zealand. Its natural habitats are open seas and rocky shores.
- Flightless Cormorant, Phalacrocorax harrisi (previously Nannopterum harrisi) (confined to the Galapagos Islands where, through evolution, its wings have shrunk to the size of a penguin's flippers)
Cormorants' fishing
Humans have historically exploited cormorants' fishing skills, in China, Japan, and Macedonia, where they have been trained by fishermen. In Japan, traditional cormorant fishing can be seen in Gifu City, in Gifu Prefecture, where it has continued uninterrupted for 1300 years, or in the city of Inuyama, in Aichi Prefecture. In Guilin, China, cormorant birds are famous for fishing on the shallow Lijiang River. A snare is tied near the base of the bird's throat, a snare that allows the bird only to swallow small fish. When the bird captures and tries to swallow a large fish, the fish gets stuck in the bird's throat. When the bird returns to the fisherman's raft, the fisherman helps the bird to remove the fish from its throat. The method is not as common today, since more efficient methods of catching fish have been developed.
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