Flightless cormorant

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Flightless cormorant
Scientific classification
Kingdom Information
Domain	Eukaryota
Kingdom	Animalia
Subkingdom	Bilateria
Branch	Deuterostomia
Phylum Information
Phylum	Chordata
Sub-phylum	Vertebrata
Infraphylum	Gnathostomata
Class Information
Superclass	Tetrapoda
Class	Aves
Sub-class	Neornithes
Order Information
Order	Suliformes
Family Information
Family	Phalacrocoracidae
Genus Information
Genus	Phalacrocorax
Species Information
Species	P. harrisi
Synonyms	Compsohalieus harrisi Nannopterum harrisi
Population statistics
Population	2,030 (2013 est.)[1]
Conservation status	Vulnerable[2]

The flightless or Galapagos cormorant (Phalacrocorax harrisi) is a species of cormorant of the family Phalacrocoracidae, and found on the Galapagos Islands of Ecuador.

Description[edit]

The flightless cormorant is the largest known cormorant species, about 35 to 39.5 inches in length and weighing 5.5 to 11 pounds, about twice as heavy as their flight-capable relatives. Males are about one-third larger than females. Adult plumage is blackish above, fading into a grayish-brown below. The beak is long and hooked, and they bear blue eyes. Juveniles are black overall, with dark colored eyes. When the bird is hot, it will rapidly flap its neck membranes to keep cool, in what biologists call "gular fluttering"^[3].

The wings are what gives the bird its name. They are small and stubby-looking; in comparison to other cormorants they are about one-third the size. Primary and secondary feathers - normally the flight feathers on any other bird - are reduced in size and bear a ragged appearance. Unlike penguins, which use their wings as the means of propulsion in the water, flightless cormorants hold their wings close to the body, and use their large webbed feet to propel themselves.

The call is described as a low type of growling, made during the breeding season; they are largely silent throughout the year^[4].

Range and habitat[edit]

The flightless cormorant is found in the Galapagos archipelago, specifically on two islands: Fernandina, and north and west Isabela Island. It is found on rocky, low-lying lava-based outcrops, from sea level to rarely more than 300 feet inland.

Reproduction[edit]

Courtship begins with the birds swimming parallel in the water next to each other, with the necks so strongly-curved that the beak touches the goiter. They croak occasionally and from time to time one of them will align and shake. After 20 to 80 minutes, the male leads the female to the bank, continuing the courtship with deep bows, alternately pointing the beak skyward and to the ground, and often holding nesting material.

The pair is not monogamous; females can breed two or three times a year with different partners, and they will leave the nest before the chicks are fledged to seek out the new partner^[5]. Up to three eggs are laid in the nest, and from the clutch usually only one chick survives. The population on the islands is limited by the availability of food, possibly jeopardizing the survival of the chicks more than that of the parents; the frequent breeding, however, may ensure a recovery should the overall population have a decline.

Threats[edit]

The flightless cormorant has been classified by the ICUN as "vulnerable", due to the physical characteristics of the bird, its restricted location, and the fact that it is vulnerable to climatic conditions and introduced predators^[6]. For the former, it has been documented that events such as El Niño will kill off a number of birds, such as the 1983 event^[7] which reduced the population to 400 birds; their prolific breeding enabled a recovery within a season. With regard to the latter, the species - isolated from natural predators on the islands - found itself the victim of introduced domestic dogs, cats, and several species of rat. And local populations on the island of Fernandina are at risk due to the island's unpredictable volcanic activity.

Human activity has also been cited as a threat. 100,000-plus tourists land on the islands yearly, with possible impacts on breeding. In addition, illegal fishing around both of its islands has included the birds as a snagged by-catch, while potential oil spills remain a constant threat^[8].

References[edit]

1. ↑ https://www.iucnredlist.org/species/22696756/133546087#population
2. ↑ https://www.iucnredlist.org/species/22696756/133546087
3. ↑ https://www.audubon.org/news/how-birds-keep-their-cool
4. ↑ https://www.xeno-canto.org/species/Phalacrocorax-harrisi
5. ↑ https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1474-919X.1966.tb07270.x
6. ↑ http://www.oiseaux-birds.com/card-flightless-cormorant.html
7. ↑ https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JC092iC13p14437
8. ↑ https://www.newscientist.com/article/dn2372-galapagos-oil-spill-devastated-marine-iguanas/