Flightless cormorant | |
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Elizabeth Bay, Isabela Island, Galapagos | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Suliformes |
Family: | Phalacrocoracidae |
Genus: | Nannopterum |
Species: | N. harrisi |
Binomial name | |
Nannopterum harrisi (Rothschild, 1898) | |
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Synonyms | |
Phalacrocorax harrisi |
The flightless cormorant (Nannopterum harrisi), also known as the Galapagos cormorant, is a cormorant endemic to the Galapagos Islands, and an example of the highly unusual fauna there. It is unique in that it is the only known cormorant that has lost the ability to fly. It was placed in its own genus, Nannopterum , but then was later placed with most of the other cormorants in the genus Phalacrocorax . [2] A 2014 study supported reclassifying it and two other American cormorant species back into Nannopterum. [3] The IOC followed this classification in 2021. [4]
The flightless cormorant is the largest extant member of its family, 89–100 cm (35–39.5 in) in length and weighing 2.5–5.0 kg (5.5–11.0 lb), and its wings are about one-third the size that would be required for a bird of its proportions to fly. The keel on the breastbone, where birds attach the large muscles needed for flight, is also significantly reduced.
Like all cormorants, this bird has webbed feet and sturdy legs that propel it through the water as it seeks its prey of fish, small octopuses, and other little marine creatures. The species feeds near the sea floor and no more than 200 metres offshore. [5] The flightless cormorants look slightly like a duck, except for their short, stubby wings. The upperparts are blackish, and the underparts are brown. The long beak is hooked at the tip and the eye is turquoise. Like all members of the cormorant family, all four toes are joined by webbed skin. Males and females are similar in appearance, although males are larger and ca. 35% heavier. [6] Juveniles generally resemble adults but differ in that they are glossy black in colour with a dark eye. Adults produce low growling vocalizations.
Like other cormorants, this bird's feathers are not waterproof, and they spend time after each dive drying their small wings in the sunlight. Their flight and contour feathers are much like those of other cormorants, but their body feathers are much thicker, softer, denser, and more hair-like. They produce very little oil from their preen gland; it is the air trapped in the dense plumage that prevents them from becoming waterlogged.
This unique cormorant is endemic to the Galapagos Islands, [7] Ecuador, where it has a very restricted range. It is found on just two islands; Fernandina, and the northern and western coasts of Isabela. Distribution associates with the seasonal upwelling of the eastward flowing Equatorial Undercurrent (or Cromwell Current) which provides cold nutrient rich water to these western islands of the archipelago. The population has undergone severe fluctuations; in 1983 an El Niño-Southern Oscillation (ENSO) event resulted in a 50% reduction of the population to just 400 individuals. The population recovered quickly, however, and was estimated to number 900 individuals by 1999.
This species inhabits the rocky shores of the volcanic islands on which it occurs. It forages in shallow coastal waters, including bays and straits. Flightless cormorants are extremely sedentary, remaining most or all of their lives, and breeding, on local stretches of coast-line several hundred metres long. [8] Their sedentary nature is reflected in a genetic differentiation between the main colonies, and particularly between Fernandina and Isabela Island. [9]
Nesting tends to take place during April–October, [8] [10] when sea surface temperatures are coldest resulting in an abundance of marine food, and the risk of heat stress to the chicks is decreased. At this time, breeding colonies consisting of up to about 12 pairs form. The courtship behavior of this species begins in the sea; the male and female swim around each other with their necks bent into a snake-like position. They then move onto land. Items of seaweed (and also flotsam e.g. rope fragments) are brought predominantly by the male and gifted to the female to be woven into a bulky nest, just above high water mark.
The female generally lays three whitish eggs per clutch, though usually only one chick survives. Both male and female share equally in incubation. Once the eggs have hatched, both parents continue to share responsibilities of brooding (protecting the chicks from exposure to heat and cold, and predation) and feeding the offspring, although the female provides 40-50% more food items than her partner. As the chicks approach independence at 70 days old and if food supplies are plentiful, the female will desert the offspring leaving the male to carry out further parenting, and she will re-partner and breed with a new mate. [11] Thus, females, but not males, can raise several broods in a single season, although studies over a decade indicate that environmental conditions allowing sufficient food availability for this, occur infrequently. [8]
Annual survival of both sexes is ca. 90%, [8] and longevity is ca. 13 years. [12] Recruitment into the population by breeding is sufficient to maintain a stable population. [8] [13]
These cormorants evolved on an island habitat that was free of predators. Having no enemies, taking its food primarily through diving along the food-rich shorelines, and not needing to travel to breeding grounds, the bird eventually became flightless. Indeed, wings trapping air among flight feathers are likely to have been a disadvantage to the cormorants which dive from the surface. However, since their discovery by man, the islands have not remained free of predators: cats, dogs, and pigs have been introduced to the islands over the years. In addition, these birds have no fear of humans and can easily be approached and picked up.
In the past, introduced feral dogs were a great threat to the species on Isabela, but they have since been eradicated from the island. Future introduction of rats or cats to Fernandina is a huge potential threat to the species. Fishing with nets poses a current threat to the species; this not only reduces the availability of the cormorant's food, but also often results in birds becoming caught in the nets and killed.
Seasonal cold water has shaped the breeding strategy of flightless cormorants. [8] [10] [13] A rise of several degrees of sea surface temperature during the breeding season or persisting throughout the breeding season (i.e. during ENSO events) results in low breeding success. ENSO events appears to have increased in frequency and severity in recent decades, [14] possibly associated with climate change. [15] A large oil spill would pose a threat. However, although the flightless cormorant population is small and its range limited, the ability of the species to breed quickly can allow it to recover from disasters as long as the population remains above a critical level.
The flightless cormorant is one of the world's rarest birds. A survey carried out by the Charles Darwin Research Station in 2004 indicated that the species has a population of about 1,500 individuals. In 2009, BirdLife International set the number of individuals of the flightless cormorant at only 900 individuals, although a more recent estimate in 2011 was 1679 individuals. It was formerly classified as Endangered by the IUCN, but recent research shows that it is not as rare as previously believed and that its population has stabilized. Consequently, it was downlisted to Vulnerable in 2011. [1]
All populations of this species are found within the Galapagos National Park and Marine Reserve; furthermore, the archipelago was designated as a World Heritage Site in 1978. The Charles Darwin Research Station has monitored the species regularly to keep track of fluctuations in numbers over time. Conservation proposals include the continuation of annual monitoring programs, restriction on human visitation within the species range, and the prevention of fishing with nets in the bird's foraging range.
A subplot of the 2003 film Master and Commander: The Far Side of the World sees Royal Navy surgeon and naturalist Stephen Maturin (Paul Bettany) discovering and then searching for flightless cormorants in the Galapagos Islands during the Napoleonic wars in 1805. In the film's last line, the ship's captain Jack Aubrey (Russell Crowe) tells Maturin, who is anxious to return to the Galapagos to capture the bird, that "it's not going anywhere." [16] In reality Nannopterum harrisi would not be formally discovered until 1897 by the species' namesake, naturalist Charles Miller Harris, on an expedition sponsored by Walter Rothschild, who chose the name. [17]
Phalacrocoracidae is a family of approximately 42 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 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. It breeds in much of the Old World, Australasia, and the Atlantic coast of North America.
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 spectacled cormorant or Pallas's cormorant is an extinct marine bird of the cormorant family of seabirds that inhabited Bering Island and possibly other places in the Commander Islands and the nearby coast of Kamchatka in the far northeast of Russia. The modern distribution was shown to be a relict of a wider prehistoric distribution in 2018 when fossils of the species from 120,000 years ago were found in Japan. It is the largest species of cormorant known to have existed.
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 spotted shag or pārekareka is a species of cormorant endemic to New Zealand. Though originally classified as Phalacrocorax punctatus, it is sufficiently different in appearance from typical members of that genus that for a time it was placed in a separate genus, Stictocarbo, along with a similar species, the Pitt shag. Subsequent genetic studies show that the spotted shag's lineage is nested within the typical shags.
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.
Nannopterum is a genus of cormorant comprising three species. They are found throughout the Americas, hence the common name American cormorants.
The marine iguana, also known as the sea iguana, saltwater iguana, or Galápagos marine iguana, is a species of iguana found only on the Galápagos Islands (Ecuador). Unique among modern lizards, it is a marine reptile that has the ability to forage in the sea for algae, which makes up almost all of its diet. Marine iguanas are the only extant lizard that spends time in a marine environment. Large males are able to dive to find this food source, while females and smaller males feed during low tide in the intertidal zone. They mainly live in colonies on rocky shores where they bask after visiting the relatively cold water or intertidal zone, but can also be seen in marshes, mangrove swamps and beaches. Large males defend territories for a short period, but smaller males have other breeding strategies. After mating, the female digs a nest hole in the soil where she lays her eggs, leaving them to hatch on their own a few months later.
The Galápagos Islands are off the west coast of South America straddling the equator. The Galápagos are located at the confluence of several currents including the cold Humboldt Current travelling north from South America and the Panama Current travelling south from Central America. These currents cool the islands and provide the perfect environment for the wildlife there.
Isabela Canton is a canton of Galápagos Province, Ecuador, consisting of the islands of Isabela Island, Darwin, Fernandina, Wolf, and some minor islets. Isabela is the largest island in the Galápagos, and well known for its beaches, bays and coastal lagoons with a wide variety of plants and birds. The capital of the canton is Puerto Villamil.
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 Campbell shag, also known as the Campbell Island shag, is a species of bird in the family Phalacrocoracidae. It is endemic to Campbell Island. Its natural habitats are open seas and rocky shores. It is a medium-sized bird, around 63 cm in length, with a wingspan of 105 cm, weighing between 1.6 – 2 kg. They only breed on Campbell Island and forage within 10 km of the island. Its unique, looped head and elongated beak allow to easily feed on shellfish and marine invertebrates. This is done through foraging dive cycles of high speed and efficiency.
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 Galápagos penguin is a penguin endemic to the Galápagos Islands of Ecuador. It is the only penguin found north of the equator. Most inhabit Fernandina Island and the west coast of Isabela Island. The cool waters of the Humboldt and Cromwell Currents allow it to survive despite the tropical latitude. The Galápagos penguin is one of the banded penguins, the other species of which live mostly on the coasts of Africa and mainland South America. Due to their warm environment, Galápagos penguins have developed techniques to stay cool. The feathers on their back, flippers, and head are black, and they have a white belly and a stripe looping from their eyes down to their neck and chin. Each penguin keeps only one mate, and breeds year-round. Because there is no soft areas to nest, their nests are typically in caves and crevices which also provide protection against predators and the harsh environment. The Galápagos penguin has a lifespan of 20 years, but due to predation, life expectancy in the wild could be significantly reduced. They have been critically impacted to the point of endangerment by climate change and pollution caused by plastic waste due to tourism and urbanization.
The order Suliformes is an order of birds recognised by the International Ornithologist's Union. Regarding 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).
Patricia G. Parker is a North American evolutionary biologist who uses molecular techniques to assess social structures, particularly in avian populations. Her interests have shaped her research in disease transmission and population size, particularly in regard to bird conservation. She received her B.S. in Zoology in 1975 and her Ph.D. in Behavioral Ecology in 1984, both from the University of North Carolina at Chapel Hill. From 1991 to 2000, Parker was an Assistant and Associate Professor in the Department of Evolution, Ecology, and Organismal Biology at Ohio State University. From 2000 to 2022, she was the Des Lee Professor of Zoological Studies at the University of Missouri–St. Louis.
The Crozet shag, also known as the South Georgia cormorant, is a marine cormorant native to the Crozet, Prince Edward and Marion islands in the South Atlantic Ocean.
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.