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, is a species of

cormorant 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) ado ...

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 considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. 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

species.

Taxonomy

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. 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 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 adaptation, adapted to life within the marine ecosystem, marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent ...

, 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 sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

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 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. File:Phalacrocorax gaimardi (inmate).jpg, Phalacrocorax gaimardi (immature) File:Phalacrocorax gaimardi 00.jpg, ''Poikilocarbo gaimardi'' (adult) File:Lile, Puñihuil 25feb14.jpg, ''P. gaimardi'' in flight in Chiloé, Chile

Distribution and habitat

The red-legged cormorant is native to the coast of

. On the Pacific coast it ranges from Macabi Island,

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

to Chiloe Island,

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

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

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

. It rarely occurs further south than the

Strait of Magellan The Strait of Magellan (), also called the Straits of Magellan, is a navigable sea route in southern Chile separating mainland South America to the north and the Tierra del Fuego archipelago to the south. Considered the most important natura ...

.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 generally a small island. Definitions vary, and are not precise, but some suggest that an islet is a very small, often unnamed, island with little or no vegetation to support human habitation. It may be made of rock, sand and/ ...

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 m ...

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 or committed romantic, ''de facto'' relationship. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marri ...

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 ensue, followed by copulation. Red-legged cormorant pairs are observed to be

monogamous Monogamy ( ) is a relationship of two individuals in which they form a mutual and exclusive intimate partnership. Having only one partner at any one time, whether for life or serial monogamy, contrasts with various forms of non-monogamy (e.g. ...

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 Guano (Spanish from ) is the accumulated excrement of seabirds or bats. Guano is a highly effective fertiliser due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. Guano was also, to a le ...

, 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 Precocial species in birds and mammals are those in which the young are relatively mature and mobile from the moment of birth or hatching. They are normally nidifugous, meaning that they leave the nest shortly after birth or hatching. Altricial ...

, 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 environm ...

, 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 A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

, specifically including eels,

sprat Sprat is the common name applied to a group of forage fish belonging to the genus ''Sprattus'' in the Family (biology), family Clupeidae. The term also is applied to a number of other small sprat-like forage fish (''Clupeoides'', ''Clupeonella ...

, 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 ...

, as well as

planktonic Plankton are the diverse collection of organisms that drift in water (or air) but are unable to actively propel themselves against currents (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they pro ...

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s and

squid A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...

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 5,00 ...

Status and conservation

The cormorant is considered to be

Near Threatened A near-threatened species is a species which has been Conservation status, categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to Endangered species, endangerment in the ne ...

on the

IUCN Red List of Threatened Species The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological spe ...

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, pa ...

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.

References

External links

* * {{Taxonbar, from1=Q82988231, from3=Q764712, from2=Q82988380 red-legged cormorant Birds of Peru Birds of Chile Birds of Patagonia Western South American coastal birds Fauna of Temperate South America red-legged cormorant red-legged cormorant red-legged cormorant Taxonomy articles created by Polbot