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,Nelson, J. B. 2005. Cormorants and shags. Pages 512–14. In C. M. Perrins, W. J. Bock and J. Kikkawa, eds. Pelicans, Cormorants, and their Relatives. Oxford University Press, New York. is a species of cormorant resident to the coastline of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...

. It is the only member of the genus ''Poikilocarbo.'' It is non-colonial unlike most

seabirds Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same envi ...

. The red-legged cormorant has not been observed wing-spreading, which is unusual among cormorant species.Johnsgard, P. A. 1993. Cormorants and shags (Phalacrocoracidae). Pages 311–314 In A. Matthew, ed. Cormorants, Darters and Pelicans of the World. Smithsonian Institution Press, Washington.

Taxonomy

The red-legged cormorant is placed within the genus ''Phalacrocorax'', but it has been debated that it should be placed within ''Notocarbo'' as phylogenetic studies suggest that it is most closely related to other southern-hemisphere shags, such as the spotted shag.del Hoya, J., Elliot, A. and Sargatal, J. 1992. Family Phalacrocoracidae (cormorants) species accounts. Pages 351–352. In R. Mascort, ed. Handbook of the Birds of the World Volume I Ostrich to Ducks. Lynx Edicions, Barcelona. 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''. This classification was followed by the

IOC The International Olympic Committee (IOC; french: link=no, Comité international olympique, ''CIO'') is a non-governmental sports organisation based in Lausanne, Switzerland. It is constituted in the form of an association under the Swiss ...

in 2021. 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. ''Poikilocarbo'' is thought to have diverged from the rest of the Phalacrocoracidae between 12.0 - 13.5 million years ago.

Description

The red-legged cormorant is a medium-sized

seabird Seabirds (also known as marine birds) are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same enviro ...

, with a long neck, streamlined body, webbed feet and a long, thin hooked bill. Its body length is , with an average wingspan of . It weighs . There is no

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most an ...

between the male and female birds.Red-legged cormorant (''Phalacrocorax gaimardi''). ARKive. http://www.arkive.org/red-legged-cormorant/phalacrocorax-gaimardi/#text=Glossary . October 14th, 2011. 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

filoplume Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and a premier ...

s behind the eyes and down the neck. The

wing coverts A covert feather or tectrix on a bird is one of a set of feathers, called coverts (or ''tectrices''), which, as the name implies, cover other feathers. The coverts help to smooth airflow over the wings and tail. Ear coverts The ear coverts are s ...

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 Gular skin (throat skin), in ornithology, is an area of featherless skin on birds that joins the lower mandible of the beak (or ''bill'') to the bird's neck. Other vertebrate taxa may have a comparable anatomical structure that is referred to as ...

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.

Distribution and habitat

The red-legged cormorant is native to the coast of

. On the Pacific coast it ranges from Macabi Island,

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = National seal , national_motto = "Firm and Happy f ...

to Chiloe Island,

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

. There are small isolated populations on the Atlantic coast scattered across Santa Cruz,

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

. It rarely occurs further south than the Strait of Magellan.Harrison, P. 1983. Family Phalacrocoracidae cormorants, shags. Pages 122 and 304. In Seabirds, An Identification Guide. Houghton Mifflin Company, Boston. Red-legged cormorants nest sparsely on steep rock faces, including coastal cliffs, rocky

islet An islet is a very small, often unnamed island. Most definitions are not precise, but some suggest that an islet has little or no vegetation and cannot support human habitation. It may be made of rock, sand and/or hard coral; may be permanen ...

s, 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. They

forage Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used ...

within inshore bodies of water and in shallow offshore waters.

Behaviour

Breeding

The red-legged cormorant is a non-colonial

, instead living in pairs or small groups.

Courtship Courtship is the period wherein some couples get to know each other prior to a possible marriage. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marriage. A courtship may be an informal and private m ...

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. When the female advances, the male displays a throwback posture; outstretching the neck and pointing the bill towards the tail. The female may respond to the male's display by hopping and throat clicking. When the female selects a male, periods of

allopreening Preening is a found in birds that involves the use of the beak to position feathers, interlock feather that have become separated, clean plumage, and keep ectoparasites in check. Feathers contribute significantly to a bird's insulation, waterp ...

ensue, followed by

copulation Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetra ...

. Red-legged cormorant pairs are observed to be monogamous for at least one season. Nests are constructed on steep cliffs and are usually isolated from other birds, but can form small colonies on rare occasions. They are composed of feathers, guano, seaweed, the cases of tube-dwelling worms and even garbage. They have been observed diving 8 to 10 meters collecting billfulls of various nesting materials. Egg laying takes place between October and January, with clutch sizes averaging three eggs. After hatching, the nestlings initially have no feathers, but are quickly covered in brownish down. As with all cormorants, nestlings are

altricial In biology, altricial species are those in which the young are underdeveloped at the time of birth, but with the aid of their parents mature after birth. Precocial species are those in which the young are relatively mature and mobile from the mome ...

, incubation period averages 30 days and the chick-rearing period is 60–70 days.

Feeding

Red-legged cormorants are generally solitary

rs, but hunting in pairs or small flocks may occur. Most red-legged cormorants forage no further than 3 km away from their nest. They hunt in inshore waters, including

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environmen ...

, and in shallow offshore waters. They never enter exclusively fresh water. 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. They can dive below the surface in pursuit of prey. Their diet mainly consists of

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of ...

, specifically including

eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...

s and

anchovies An anchovy is a small, common forage fish of the family Engraulidae. Most species are found in marine waters, but several will enter brackish water, and some in South America are restricted to fresh water. More than 140 species are placed in 1 ...

, and planktonic

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

Voice

The red-legged cormorants calls are unlike most

; they consist of high-pitched chirps and chirrups more like a

songbird A songbird is a bird belonging to the suborder Passeri of the perching birds (Passeriformes). Another name that is sometimes seen as the scientific or vernacular name is Oscines, from Latin ''oscen'', "songbird". The Passeriformes contains 5000 ...

Status and conservation

The cormorant is considered to be

Near Threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify f ...

on the IUCN Red List of Threatened Species.

Predation

Due to the birds' habit of nesting on cliffs with sheer rock faces and no ground approach, they are inaccessible to most predators. Their main predators are

kelp gull The kelp gull (''Larus dominicanus''), also known as the Dominican gull, is a gull that breeds on coasts and islands through much of the Southern Hemisphere. The nominate ''L. d. dominicanus'' is the subspecies found around South America, part ...

s, as well as humans, who consume adults, nestlings and eggs. 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.