Red-legged cormorant | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Suliformes |
Family: | Phalacrocoracidae |
Genus: | Poikilocarbo Boetticher, 1935 |
Species: | P. gaimardi |
Binomial name | |
Poikilocarbo gaimardi (Garnot, 1828) | |
The red-legged cormorant (Poikilocarbo gaimardi), also known as the red-legged shag, red-footed cormorant, red-footed shag, Gaimard's cormorant and grey cormorant, [2] is a species of cormorant resident to the coastline of South America. It is the only member of the genus Poikilocarbo. [3] It is non-colonial unlike most seabirds. The red-legged cormorant has not been observed wing-spreading, which is unusual among cormorant species. [4]
The red-legged cormorant was traditionally placed within the genus Phalacrocorax, but this assignment has been contested in recent years. Some phylogenetic studies have suggested that this species should be placed within Notocarbo, finding it to be most closely related to other southern-hemisphere shags, such as the spotted shag. [5] A 2014 study found it to represent the second most basal genus of cormorant, with only Microcarbo being more basal, and thus reclassified into the genus Poikilocarbo. [6] This classification was followed by the IOC in 2021. [7] It has been suggested that the population of red-legged cormorants on the Atlantic coast are a separate subspecies. They are slightly smaller and have marginally paler plumage compared to the birds of the Pacific coast. [2] [4]
Poikilocarbo is thought to have diverged from the rest of the Phalacrocoracidae between 12.0 - 13.5 million years ago. [8]
The red-legged cormorant is a medium-sized seabird, with a long neck, streamlined body, webbed feet and a long, thin hooked bill. Its body length is 71–76 centimetres (28–30 in), with an average wingspan of 91 cm (36 in). [5] It weighs 1.3–1.5 kilograms (2.9–3.3 lb). [4] There is no sexual dimorphism between the male and female birds. [9]
The red-legged cormorant's appearance is unmistakable. Breeding adults have a smoky grey body, with a slightly paler underside. They have scattered areas of white filoplumes behind the eyes and down the neck. The wing coverts have a speckled, silvery grey appearance, followed by broad black wing tips. The tail is also black. The eyes are green, surrounded by sixteen tiny blue marks. The bill is yellow, shading to orange toward the base, the gular skin is a vibrant orange or red. The legs and feet are a striking coral red.
Non-breeding adults look similar to breeding adults. They lack the white filoplumes, the wing coverts appear less silvery, but more dark grey, and the bill and gular skin are duller in colouration.
Juvenile red-legged cormorants usually possess paler, brown plumage with a speckling of white around the throat. Juvenile plumage colouration can be highly variable between the Atlantic and Pacific coasts. Their eyes are grey and their bills and gular skin range from black to orange. The legs and feet can be a dull orange to a reddish black. [2] [4] [10]
The red-legged cormorant is native to the coast of South America. On the Pacific coast it ranges from Macabi Island, Peru to Chiloe Island, Chile. There are small isolated populations on the Atlantic coast scattered across Santa Cruz, Argentina. [4] It rarely occurs further south than the Strait of Magellan. [11]
Red-legged cormorants nest sparsely on steep rock faces, including coastal cliffs, rocky islets, and sea caverns. They become virtually undetectable against these rocky outcrops by their speckled grey plumage, with the exception of their colourful bills and feet. [4] They forage within inshore bodies of water and in shallow offshore waters. [12]
The red-legged cormorant is a non-colonial seabird, instead living in pairs or small groups. Courtship typically occurs in January and February. The males can engage in elaborate mating displays, which include darting and throwback postures. During darting, males chirp quietly while moving the head back and forth exposing the interior of the mouth. [4] When the female advances, the male displays a throwback posture; outstretching the neck and pointing the bill towards the tail. [2] The female may respond to the male's display by hopping and throat clicking. When the female selects a male, periods of allopreening ensue, followed by copulation. Red-legged cormorant pairs are observed to be monogamous for at least one season. [4]
Nests are constructed on steep cliffs and are usually isolated from other birds, but can form small colonies on rare occasions. [11] They are composed of feathers, guano, seaweed, the cases of tube-dwelling worms and even garbage. [9] [13] They have been observed diving 8 to 10 meters collecting billfulls of various nesting materials. [4] Egg laying takes place between October and January, with clutch sizes averaging three eggs. [5] After hatching, the nestlings initially have no feathers, but are quickly covered in brownish down. [4] As with all cormorants, nestlings are altricial, incubation period averages 30 days and the chick-rearing period is 60–70 days. [2] [4]
Red-legged cormorants are generally solitary foragers, but hunting in pairs or small flocks may occur. [2] Most red-legged cormorants forage no further than 3 km away from their nest. They hunt in inshore waters, including estuaries, and in shallow offshore waters. [12] They never enter exclusively fresh water. [4] Many red-legged cormorants forage at low tide, presumably to minimize their travel time to and from the surface and to maximize time searching for food. [12] They can dive 8–10 metres (26–33 ft) below the surface in pursuit of prey. Their diet mainly consists of fish, specifically including eels and anchovies, and planktonic crustaceans. [2]
The red-legged cormorants calls are unlike most seabirds; they consist of high-pitched chirps and chirrups more like a songbird. [2]
The cormorant is considered to be Near Threatened on the IUCN Red List of Threatened Species. [1]
Due to the birds' habit of nesting on cliffs with sheer rock faces and no ground approach, they are inaccessible to most predators. [2] Their main predators are kelp gulls, [14] as well as humans, who consume adults, nestlings and eggs. [2] [9] The red-legged cormorant's threat display appears to be underdeveloped, consisting only of gaping and thrusting the bill towards the intruder. This could be due to its solitary life and lack of predators. [2]
The darters, anhingas, or snakebirds are mainly tropical waterbirds in the family Anhingidae, which contains a single genus, Anhinga. There are four living species, three of which are very common and widespread while the fourth is rarer and classified as near-threatened by the IUCN. The term snakebird is usually used without any additions to signify whichever of the completely allopatric species occurs in any one region. It refers to their long thin neck, which has a snake-like appearance when they swim with their bodies submerged, or when mated pairs twist it during their bonding displays. "Darter" is used with a geographical term when referring to particular species. It alludes to their manner of procuring food, as they impale fishes with their thin, pointed beak. The American darter is more commonly known as the anhinga. It is sometimes called "water turkey" in the southern United States; though the anhinga is quite unrelated to the wild turkey, they are both large, blackish birds with long tails that are sometimes hunted for food.
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.
Brandt's cormorant is a strictly marine bird of the cormorant family of seabirds that inhabits the Pacific coast of North America. It ranges, in the summer, from Alaska to the Gulf of California, but the population north of Vancouver Island migrates south during the winter. Its specific name, penicillatus is Latin for a painter's brush, in reference to white plumes on its neck and back during the early breeding season. The common name honors the German naturalist Johann Friedrich von Brandt of the Academy of Sciences at St. Petersburg, who described the species from specimens collected on expeditions to the Pacific during the early 19th century.
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 great cormorant, 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. The genus name is Latinised Ancient Greek, from φαλακρός and κόραξ, and carbo is Latin for "charcoal".
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 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 little cormorant is a member of the cormorant family of seabirds. Slightly smaller than the Indian cormorant it lacks a peaked head and has a shorter beak. It is widely distributed across the Indian Subcontinent and extends east to Java, where it is sometimes called the Javanese cormorant. It forages singly or sometimes in loose groups in lowland freshwater bodies, including small ponds, large lakes, streams and sometimes coastal estuaries. Like other cormorants, it is often found perched on a waterside rock with its wings spread out after coming out of the water. The entire body is black in the breeding season but the plumage is brownish, and the throat has a small whitish patch in the non-breeding season. These birds breed gregariously in trees, often joining other waterbirds at heronries.
The Otago shag, together with the Foveaux shag formerly known as the Stewart Island shag and in its dark phase as the bronze shag, is a species of shag now found only in coastal Otago, New Zealand.
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 Cape cormorant or Cape shag is a bird endemic to the southwestern coasts of Africa.
The Socotra cormorant is a threatened species of cormorant that 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. Despite its name, it was only confirmed in 2005 that it breeds on the Socotra islands in the Indian Ocean.
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 black-faced cormorant, also known as the black-faced shag, is a medium-sized member of the cormorant family. Upperparts, including facial skin and bill, are black, with white underparts. It is endemic to coastal regions of southern Australia.
The Chatham shag, also known as the Chatham Island 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 Kerguelen shag is a species of cormorant endemic to the Kerguelen Islands in the southern Indian Ocean, one of the most isolated places on Earth. Many authorities consider it a subspecies of the imperial shag.
The order Suliformes is an order recognised by the International Ornithologist's Union. In regard to the recent evidence that the traditional Pelecaniformes is polyphyletic, it has been suggested that the group be divided to reflect the true evolutionary relationships; a 2017 study indicated that they are most closely related to Otidiformes (bustards) and Ciconiiformes (storks).
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.
The Foveaux shag, together with the Otago shag formerly known as the Stewart Island shag and in its dark phase as the bronze shag, is a species of shag endemic to Stewart Island/Rakiura and Foveaux Strait, from which it takes its name.