Pelagic Cormorant
Encyclopedia
The Pelagic Cormorant also known as Baird's Cormorant, is a small member of the cormorant
family
Phalacrocoracidae. Analogous to other smallish cormorants, it is also called Pelagic Shag occasionally. This seabird
lives along the coasts of the northern Pacific; during winter it can also be found in the open ocean
.
Presently, many authors favor splitting up the "wastebin genus" Phalacrocorax. In this case, the Pelagic Cormorant would probably be placed in Compsohalieus.
This is a smallish cormorant which measures to|35|in|cm|abbr=on}} in length, with a wingspan
of about 3.3 ft (1 meter) and a weight of 52-86 oz (1474-2438 g) when fully grown. Adults in nonbreeding plumage are all-black with a metallic iridescence
. In breeding plumage they grow two short crests (one on top of the head and one at the nape
), white thigh
s, and scattered white filoplumes on the head and neck. The long thin bill
and the large feet with all-webbed toes
are black throughout the year, while the patch of dark naked skin below the eye turns a vivid magenta
in the breeding season.
Males and females do not differ in appearance, though the latter are a bit smaller. Immature birds lack iridescence and are dark brown, grading into slightly lighter brown on the underside.
The widely sympatric Red-faced Cormorant
(P. urile) looks very similar. Breeding adults are easily told apart by the amount of naked facial skin, which does not noticeably extend beyond the eye in P. pelagicus, but extends to above the bill and above and behind the eye in P. urile; the latter species also has larger crests. Juveniles and nonbreeding adults of the two species
are often indistinguishable even to trained observers, if they cannot be observed up close or in mixed flocks. In the former case, the large naked face "mask" and light bill of P. urile can be easily recognized, in the latter case its larger size (though male Pelagic Cormorants can be as large as female Red-faced Cormorants). Unlike the Red-faced Cormorant, the present species usually calls out before taking off, particularly during the breeding season. In courtship display
, nest material is typically torn and moved about (which P. urile might not do) and the males apparently do not bow their heads before the females as P. urile males do. Other North Pacific cormorants and shags are larger, with a thicker bill, and/or lack the white thighs in breeding plumage.
n range extends from Alaska
to the Baja peninsula in Mexico
. It furthermore is found on the Aleutian and other Bering Strait
islands, and from the Russian Far East
Chukchi Peninsula
via Sakhalin
south to Kamchatka, and ultimately Kyūshū
(though not the rest of Japan
). The subarctic
population
s are migratory
, while the birds from temperate
and subtropical regions only disperse locally after breeding, but even so Asian birds may reach China
or Korea
. Vagrants have been recorded in the Hawaiian Islands
.
On land, Pelagic Cormorants are rather clumsy and walk with the high-stepped waddling gait typical for all Sulae except darter
s; after landing they often scratch the ground, as is typical for cormorants. When they feel threatened, they will dart the bills at the intruder, and shake their heads and make a gargling noise. This bird forages by swimming to locate prey, then diving and going after it underwater, propelled by its feet and steering with the wings. It can dive as deep as 100 ft (30.5 m) to feed on or near the seafloor. Typical hunting grounds are sheltered inlet
s and bay
s; especially outside the breeding season they can also be seen fishing out at sea. They prefer to hunt in the vicinity of kelp
beds or among rocks. Typical prey are smallish, bottom-living non-schooling fish
es, such as Ammodytes sand eel
s, sculpin
s (Cottidae), gunnel
s (Pholidae) and Sebastes
rockfish
. Apart from fish, small crustacean
s – in particular shrimp
– are also often eaten. It has been observed to join mixed-species feeding flock
s going after schools of young Pacific Herring
s (Clupea pallasii). Like in all cormorants, due to their vestigial uropygial gland
their plumage is not waterproof. Thus, the birds return to a safe place after foraging to preen
and dry their feathers, typically adopting a spread-winged posture.
The Pelagic Cormorant breeds on rocky shore
s and islands. They do not form large colonies, but smaller groups may nest together. In some cases these birds alternate between two or three nesting sites in a region from one year to another. The nest is built at the cliff face, usually on ledges, less often in crevices or caves. The nest is built from stringy plant
s, such as grass
es or seaweed
, and held together by the birds' own guano
. Once the birds have found a nest site they like, they tend to remain faithful to it for the rest of their life. The nest is repaired and improved in each season if need be; it can thus grow up to 5 ft (1.5 m) deep.
Males searching for a mate or bonding with their partner give an elaborate courtship display
, as is typical for Sulae. Like all cormorants, this includes stretching the gular sac with the hyoid bone
and repeated "yawning"; as in many but not all cormorants, the Pelagic Cormorant's display furthermore includes arching the neck and hopping, lifting the folded wings and rapidly fluttering them to show the white thigh patches. During the "yawning" display, the head is thrown back and calls are given which differ between males and females; when the birds land, males and females give an identical call. Otherwise, the displays are given in silence.
The clutch
is generally between 2 and 5 eggs
, most often 3 or 4, but clutches of up to seven eggs have been recorded. Incubation
lasts for 3 weeks to one month. At hatching, the young weigh somewhat more than an ounce (35 g) and are naked, but they soon grow soot
y-grey down feather
s. In normal years, all young of a typical clutch may be raised successfully, but less than 4 rarely fledge
. On the other hand, during unfavorable phases of the Pacific decadal oscillation
, most pairs manage to raise only two young at most. They reach sexual maturity
at two years of age, and a maximum age of almost 18 years has been recorded in the wild.
This numerous and widespread species is not considered threatened by the IUCN. The bulk of its population is found in the relatively inaccessible waters of the Bering Sea region; about 50,000 each breed in the Kuril Islands, the Bering Sea islands, and the U.S. state of Alaska and its offshore islands (including the Aleuts). About 25,000 breed down the Pacific coast of North America, some 60% of which are found in California. Local populations may be all but wiped out temporarily by oil spill
s, and on a larger scale competition with gillnet
fisheries and drowning in such nets is putting a limit to its stocks.
The acanthocephala
n parasite Andracantha phalacrocoracis was described from this cormorant.
Phalacrocoracidae has traditionally been included – like all other bird
s with fully webbed toes – in the Pelecaniformes
. But the namesake pelican
s (Pelecanidae) are actually closer relatives of stork
s (Ciconiidae) than of cormorants. Hence, it has been proposed to separate the Phalacrocoracidae and relatives as order
Phalacrocoraciformes.
This species
is here placed in the catch-all genus
Phalacrocorax. Modern authors generally are reserved about uniting all cormorants in one "wastebin genus", but no general revision has been published that has any phylogenetic merit. Though it was proposed to place the Pelagic Cormorant in Stictocarbo for example, this is quite certainly wrong, as the present species is by no means closely related to the Spotted Shag
(P. punctatus), the type species
of Stictocarbo. Similarly, Leucocarbo would refer to the group around the Imperial Shag
(P. atriceps) complex, which occurs on the opposite end of the Earth from P. pelagicus. The supposed "cliff shag" subfamily Leucocarboninae is entirely paraphyletic cannot be accepted as originally circumscribed. If subfamilies are to be accepted in the Phalacrocoracidae, the Pelagic Shag and its relatives would go in the Phalacrocoracinae like most Northern Hemisphere
cormorants and shags, while Leucocarboninae would include mainly Southern Hemisphere
taxa.
In fact, the correct genus
name for the Pelagic Cormorant, if Phalacrocorax is to be split up, would be Compsohalieus. This name would apply to the group around its type species
(Brandt's Cormorant
, P. penicillatus). This is a North Pacific clade
, which apart from Brandt's and the Pelagic Cormorant also includes the Red-faced Cormorant
(P. urile) and probably also the extinct Spectacled Cormorant
(P. perspicillatus). They all have black feet, and in breeding plumage grow white filoplumes on the head and/or neck, and usually also two head-crests and white thigh
patches like the present species does. They also share the back-thrown head during the "yawning" and the rapid wing-flutter in courtship display
. Among the Compsohalieus group, the Red-faced Cormorant is the sister species of P. pelagicus. Apart from loking almost alike, these two species also "yawn" many times in a row instead of giving the display just once, twist their bodies before taking flight during courtship, and the male and female post-landing calls are identical. The point-and-gargle response to threats is also an apomorphy of these two species.
Its traditional scientific name is the literal Latin
ized Ancient Greek
equivalent of the common name: Phalacrocorax is an ancient term for cormorants; literally, it means "bald raven
", from falakrós (φᾶλακρός, "bald") + kórax (κόραξ, "raven"). pelagicus is – like the English loanword
"pelagic" – derived from pelágios (πελᾶγιος, "of the open seas"). Compsohalieus, meanwhile, means "sleek fisher"; it derives from kompsós (κομψός, "elegant" or "sleek") + (h)alieus (ἇλιεύς, "fisherman").
are generally recognized. The difference between them is slight and generally agrees with Bergmann's Rule
:
The Amchitka Cormorant or Kenyon's Shag (P. kenyoni) is a supposed species
that was presumed to be closely related to the Pelagic Cormorant. It was described from the bones of three individuals snared in fishing nets in the late 1950s at Constantine Harbor
on Amchitka in the Aleutian Islands. The specific name kenyoni honors USFWS biologist
Karl W. Kenyon, who collected the type specimen USNM 431164 on 22 February 1959. Some bones from prehistoric middens on Amchitka were also attributed to this taxon
. As distinctive cormorants were never seen alive in recent years on Amchitka, it was conjectured by some that Kenyon's Shag might have gone extinct in the 1960s-1970s (marine pollution
and overfishing
would be possible reasons).
However, a subsequent analysis of a larger number of comparison specimens of the Pelagic Cormorant – mainly from birds that fell victim to the Exxon Valdez oil spill
– determined that the bones were attributable to small females of the latter species, and that their apparent distinctness was due to the original canonical analysis
being distorted by insufficient specimens. The researchers also found that contrary to what was generally assumed, Pelagic Cormorants from the Aleutians were generally small birds – as opposed to western Alaskan individuals, which are usually very large. If the Aleutian population were to be considered a distinct subspecies
, the name kenyoni would apply. Verification of subspecies status would require DNA sequence
analyses however, since the differences in morphology
are not large and there is much variation between individuals.
On 20 July 2003, during an USFWS survey three small Pelagic Cormorants whose bills appeared to be red were noted at Karab Cove on Agattu Island. It may be that these were kenyoni, but whether the bill color distinguishes the presumed subspecies or whether it is due to a simple mutation
has not been determined. The large birds from the Prince William Sound
region were formerly called P. p. robustus, but are not considered distinct today. Since there appear to be at least 2 recognizable and allopatric size groups in the northern subspecies alone, more research is clearly necessary.
Cormorant
The bird family Phalacrocoracidae is represented by some 40 species of cormorants and shags. Several different classifications of the family have been proposed recently, and the number of genera is disputed.- Names :...
family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Phalacrocoracidae. Analogous to other smallish cormorants, it is also called Pelagic Shag occasionally. This seabird
Seabird
Seabirds are birds that have 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 environmental problems and feeding niches have resulted in similar adaptations...
lives along the coasts of the northern Pacific; during winter it can also be found in the open ocean
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
.
Presently, many authors favor splitting up the "wastebin genus" Phalacrocorax. In this case, the Pelagic Cormorant would probably be placed in Compsohalieus.
Description
Wingspan
The wingspan of an airplane or a bird, is the distance from one wingtip to the other wingtip. For example, the Boeing 777 has a wingspan of about ; and a Wandering Albatross caught in 1965 had a wingspan of , the official record for a living bird.The term wingspan, more technically extent, is...
of about 3.3 ft (1 meter) and a weight of 52-86 oz (1474-2438 g) when fully grown. Adults in nonbreeding plumage are all-black with a metallic iridescence
Iridescence
Iridescence is generally known as the property of certain surfaces which appear to change color as the angle of view or the angle of illumination changes...
. In breeding plumage they grow two short crests (one on top of the head and one at the nape
Nape
The nape is the back of the neck. In technical anatomical/medical terminology, the nape is referred to by the word nucha, which also gives the adjective corresponding to "nape" in English, "nuchal"....
), white thigh
Thigh
In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...
s, and scattered white filoplumes on the head and neck. The long thin bill
Beak
The beak, bill or rostrum is an external anatomical structure of birds which is used for eating and for grooming, manipulating objects, killing prey, fighting, probing for food, courtship and feeding young...
and the large feet with all-webbed toes
Webbed toes
Webbed toes is the common name for syndactyly affecting the feet. It is characterised by the fusion of two or more digits of the feet. This is normal in many birds, such as ducks; amphibians, such as frogs; and mammals, such as kangaroos...
are black throughout the year, while the patch of dark naked skin below the eye turns a vivid magenta
Magenta
Magenta is a color evoked by light stronger in blue and red wavelengths than in yellowish-green wavelengths . In light experiments, magenta can be produced by removing the lime-green wavelengths from white light...
in the breeding season.
Males and females do not differ in appearance, though the latter are a bit smaller. Immature birds lack iridescence and are dark brown, grading into slightly lighter brown on the underside.
The widely sympatric Red-faced Cormorant
Red-faced Cormorant
The Red-faced Cormorant, Red-faced Shag or Violet Shag, Phalacrocorax urile, is a species of cormorant that is found in the far north of the Pacific Ocean and Bering Sea, from the eastern tip of Hokkaidō in Japan, via the Kuril Islands, the southern tip of the Kamchatka Peninsula and the Aleutian...
(P. urile) looks very similar. Breeding adults are easily told apart by the amount of naked facial skin, which does not noticeably extend beyond the eye in P. pelagicus, but extends to above the bill and above and behind the eye in P. urile; the latter species also has larger crests. Juveniles and nonbreeding adults of the two species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
are often indistinguishable even to trained observers, if they cannot be observed up close or in mixed flocks. In the former case, the large naked face "mask" and light bill of P. urile can be easily recognized, in the latter case its larger size (though male Pelagic Cormorants can be as large as female Red-faced Cormorants). Unlike the Red-faced Cormorant, the present species usually calls out before taking off, particularly during the breeding season. In courtship display
Courtship display
Courtship display is a special, sometimes ritualised, set of behaviours which some animals perform as part of courtship. Courtship behaviours can include special calls, postures, and movements, and may involve special plumage, bright colours or other ornamentation. A good example is the 'dancing'...
, nest material is typically torn and moved about (which P. urile might not do) and the males apparently do not bow their heads before the females as P. urile males do. Other North Pacific cormorants and shags are larger, with a thicker bill, and/or lack the white thighs in breeding plumage.
Range and ecology
The Pelagic Cormorant inhabits the shores and the neritic zone of the North Pacific. Its North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n range extends from Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
to the Baja peninsula in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. It furthermore is found on the Aleutian and other Bering Strait
Bering Strait
The Bering Strait , known to natives as Imakpik, is a sea strait between Cape Dezhnev, Chukotka Autonomous Okrug, Russia, the easternmost point of the Asian continent and Cape Prince of Wales, Alaska, USA, the westernmost point of the North American continent, with latitude of about 65°40'N,...
islands, and from the Russian Far East
Russian Far East
Russian Far East is a term that refers to the Russian part of the Far East, i.e., extreme east parts of Russia, between Lake Baikal in Eastern Siberia and the Pacific Ocean...
Chukchi Peninsula
Chukchi Peninsula
The Chukchi Peninsula, Chukotka Peninsula or Chukotski Peninsula , at about 66° N 172° W, is the northeastern extremity of Asia. Its eastern end is at Cape Dezhnev near the village of Uelen. It is bordered by the Chukchi Sea to the north, the Bering Sea to the south, and the Bering Strait to the...
via Sakhalin
Sakhalin
Sakhalin or Saghalien, is a large island in the North Pacific, lying between 45°50' and 54°24' N.It is part of Russia, and is Russia's largest island, and is administered as part of Sakhalin Oblast...
south to Kamchatka, and ultimately Kyūshū
Kyushu
is the third largest island of Japan and most southwesterly of its four main islands. Its alternate ancient names include , , and . The historical regional name is referred to Kyushu and its surrounding islands....
(though not the rest of Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
). The subarctic
Subarctic
The Subarctic is a region in the Northern Hemisphere immediately south of the true Arctic and covering much of Alaska, Canada, the north of Scandinavia, Siberia, and northern Mongolia...
population
Population
A population is all the organisms that both belong to the same group or species and live in the same geographical area. The area that is used to define a sexual population is such that inter-breeding is possible between any pair within the area and more probable than cross-breeding with individuals...
s are migratory
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
, while the birds from temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
and subtropical regions only disperse locally after breeding, but even so Asian birds may reach China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
or Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...
. Vagrants have been recorded in the Hawaiian Islands
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
.
On land, Pelagic Cormorants are rather clumsy and walk with the high-stepped waddling gait typical for all Sulae except darter
Darter
The darters or snakebirds are mainly tropical waterbirds in the family Anhingidae. 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...
s; after landing they often scratch the ground, as is typical for cormorants. When they feel threatened, they will dart the bills at the intruder, and shake their heads and make a gargling noise. This bird forages by swimming to locate prey, then diving and going after it underwater, propelled by its feet and steering with the wings. It can dive as deep as 100 ft (30.5 m) to feed on or near the seafloor. Typical hunting grounds are sheltered inlet
Inlet
An inlet is a narrow body of water between islands or leading inland from a larger body of water, often leading to an enclosed body of water, such as a sound, bay, lagoon or marsh. In sea coasts an inlet usually refers to the actual connection between a bay and the ocean and is often called an...
s and bay
Bay
A bay is an area of water mostly surrounded by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight...
s; especially outside the breeding season they can also be seen fishing out at sea. They prefer to hunt in the vicinity of kelp
Kelp
Kelps are large seaweeds belonging to the brown algae in the order Laminariales. There are about 30 different genera....
beds or among rocks. Typical prey are smallish, bottom-living non-schooling fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate 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...
es, such as Ammodytes sand eel
Sand Eel
Sand eel or sandeel is the common name used for a considerable number of species of fish. Most of them are sea fish of the genera Hyperoplus , Gymnammodytes or Ammodytes...
s, sculpin
Cottidae
The Cottidae is a family of demersal fish in the order Scorpaeniformes, suborder Cottoidei . There are about 300 species in 70 genera of Cottidae that are mostly marine and found in shallow coastal waters in the northern and arctic regions...
s (Cottidae), gunnel
Pholidae
The gunnels are a family, Pholidae, of fishes in the order Perciformes.They are elongated fishes native to the coasts of the northern Atlantic, Pacific and Arctic Oceans, where they inhabit intertidal and subtidal waters and eat crustaceans and molluscs.-Species:There are fifteen species in three...
s (Pholidae) and Sebastes
Sebastes
Sebastes is a genus of fish in the family Sebastidae , most of which have the common name of rockfish. Most of the world's almost 110 Sebastes species live in the north Pacific, although two live in the south Pacific/Atlantic and four Sebastes is a genus of fish in the family Sebastidae (though...
rockfish
Sebastidae
Sebastidae is a family of marine fish in the order Scorpaeniformes. Their common names include rockfishes, thornyheads and rockcods. Despite the latter name, they are not closely related to the cods in the genus Gadus, nor the rock cod, Lotella rhacina.Not all authorities recognise this family as...
. Apart from fish, small crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s – in particular shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
– are also often eaten. It has been observed to join mixed-species feeding flock
Mixed-species feeding flock
A mixed-species feeding flock, also termed a mixed-species foraging flock, mixed hunting party or informally bird wave, is a flock of usually insectivorous birds of different species, that join each other and move together while foraging...
s going after schools of young Pacific Herring
Pacific herring
The Pacific herring, Clupea pallasii, is a species of the herring family associated with the Pacific Ocean environment of North America and northeast Asia. This species is a silvery fish with unspined fins and a deeply forked caudal fin...
s (Clupea pallasii). Like in all cormorants, due to their vestigial uropygial gland
Uropygial gland
The uropygial gland, informally known as the preen gland, is a gland found in the large majority of birds that secretes an oil that birds use for preening. The chief compounds of preen oil are diester waxes called uropygiols....
their plumage is not waterproof. Thus, the birds return to a safe place after foraging to preen
Preen
- Birds :*Preen, personal grooming of a bird's feathers especially by using its beak*Preen gland, also called the uropygial gland, an oil gland found in many bird species*Preen oil, an oil made by the uropygial gland found in many bird species...
and dry their feathers, typically adopting a spread-winged posture.
The Pelagic Cormorant breeds on rocky shore
Rocky shore
A rocky shore is an intertidal area of seacoasts where solid rock predominates. Rocky shores are biologically rich environments, and make the ideal natural laboratory for studying intertidal ecology and other biological processes...
s and islands. They do not form large colonies, but smaller groups may nest together. In some cases these birds alternate between two or three nesting sites in a region from one year to another. The nest is built at the cliff face, usually on ledges, less often in crevices or caves. The nest is built from stringy plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
s, such as grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
es or seaweed
Seaweed
Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...
, and held together by the birds' own guano
Guano
Guano is the excrement of seabirds, cave dwelling bats, and seals. Guano manure is an effective fertilizer due to its high levels of phosphorus and nitrogen and also its lack of odor. It was an important source of nitrates for gunpowder...
. Once the birds have found a nest site they like, they tend to remain faithful to it for the rest of their life. The nest is repaired and improved in each season if need be; it can thus grow up to 5 ft (1.5 m) deep.
Males searching for a mate or bonding with their partner give an elaborate courtship display
Courtship display
Courtship display is a special, sometimes ritualised, set of behaviours which some animals perform as part of courtship. Courtship behaviours can include special calls, postures, and movements, and may involve special plumage, bright colours or other ornamentation. A good example is the 'dancing'...
, as is typical for Sulae. Like all cormorants, this includes stretching the gular sac with the hyoid bone
Hyoid bone
The hyoid bone is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies at the level of the base of the mandible in the front and the third cervical vertebra behind.Unlike other bones, the hyoid is only distantly...
and repeated "yawning"; as in many but not all cormorants, the Pelagic Cormorant's display furthermore includes arching the neck and hopping, lifting the folded wings and rapidly fluttering them to show the white thigh patches. During the "yawning" display, the head is thrown back and calls are given which differ between males and females; when the birds land, males and females give an identical call. Otherwise, the displays are given in silence.
The clutch
Clutch (eggs)
A clutch of eggs refers to all the eggs produced by birds or reptiles, often at a single time, particularly those laid in a nest.In birds, destruction of a clutch by predators, , results in double-clutching...
is generally between 2 and 5 eggs
Egg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
, most often 3 or 4, but clutches of up to seven eggs have been recorded. Incubation
Avian incubation
Incubation refers to the process by which certain oviparous animals hatch their eggs, and to the development of the embryo within the egg. The most vital factor of incubation is the constant temperature required for its development over a specific period. Especially in domestic fowl, the act of...
lasts for 3 weeks to one month. At hatching, the young weigh somewhat more than an ounce (35 g) and are naked, but they soon grow soot
Soot
Soot is a general term that refers to impure carbon particles resulting from the incomplete combustion of a hydrocarbon. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolyzed fuel particles such as cenospheres,...
y-grey down feather
Down feather
The down of birds is a layer of fine feathers found under the tougher exterior feathers. Very young birds are clad only in down. Powder down is a specialized type of down found only in a few groups of birds. Down is a fine thermal insulator and padding, used in goods such as jackets, bedding,...
s. In normal years, all young of a typical clutch may be raised successfully, but less than 4 rarely fledge
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
. On the other hand, during unfavorable phases of the Pacific decadal oscillation
Pacific decadal oscillation
The Pacific Decadal Oscillation is a pattern of Pacific climate variability that shifts phases on at least inter-decadal time scale, usually about 20 to 30 years. The PDO is detected as warm or cool surface waters in the Pacific Ocean, north of 20° N...
, most pairs manage to raise only two young at most. They reach sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
at two years of age, and a maximum age of almost 18 years has been recorded in the wild.
This numerous and widespread species is not considered threatened by the IUCN. The bulk of its population is found in the relatively inaccessible waters of the Bering Sea region; about 50,000 each breed in the Kuril Islands, the Bering Sea islands, and the U.S. state of Alaska and its offshore islands (including the Aleuts). About 25,000 breed down the Pacific coast of North America, some 60% of which are found in California. Local populations may be all but wiped out temporarily by oil spill
Oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution. The term is mostly used to describe marine oil spills, where oil is released into the ocean or coastal waters...
s, and on a larger scale competition with gillnet
Gillnet
Gillnetting is a common fishing method used by commercial and artisanal fishermen of all the oceans and in some freshwater and estuary areas. The gillnet also is used by fisheries scientists to monitor fish populations. Because gillnets can be so effective their use is closely monitored and...
fisheries and drowning in such nets is putting a limit to its stocks.
The acanthocephala
Acanthocephala
Acanthocephala is a phylum of parasitic worms known as acanthocephales, thorny-headed worms, or spiny-headed worms, characterized by the presence of an evertable proboscis, armed with spines, which it uses to pierce and hold the gut wall of its host...
n parasite Andracantha phalacrocoracis was described from this cormorant.
Taxonomy and systematics
The cormorant familyFamily (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Phalacrocoracidae has traditionally been included – like all other bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s with fully webbed toes – in the Pelecaniformes
Pelecaniformes
The Pelecaniformes is a order of medium-sized and large waterbirds found worldwide. As traditionally—but erroneously—defined, they encompass all birds that have feet with all four toes webbed. Hence, they were formerly also known by such names as totipalmates or steganopodes...
. But the namesake pelican
Pelican
A pelican, derived from the Greek word πελεκυς pelekys is a large water bird with a large throat pouch, belonging to the bird family Pelecanidae....
s (Pelecanidae) are actually closer relatives of stork
Stork
Storks are large, long-legged, long-necked wading birds with long, stout bills. They belong to the family Ciconiidae. They are the only family in the biological order Ciconiiformes, which was once much larger and held a number of families....
s (Ciconiidae) than of cormorants. Hence, it has been proposed to separate the Phalacrocoracidae and relatives as order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Phalacrocoraciformes.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
is here placed in the catch-all genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Phalacrocorax. Modern authors generally are reserved about uniting all cormorants in one "wastebin genus", but no general revision has been published that has any phylogenetic merit. Though it was proposed to place the Pelagic Cormorant in Stictocarbo for example, this is quite certainly wrong, as the present species is by no means closely related to the Spotted Shag
Spotted Shag
The Spotted Shag or Parekareka, Phalacrocorax punctatus, is a species of cormorant endemic to New Zealand. Originally classified as Phalacrocorax punctatus, it is sufficiently different in appearance from typical members of that genus that to be for a time placed in a separate genus, Stictocarbo,...
(P. punctatus), the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of Stictocarbo. Similarly, Leucocarbo would refer to the group around the Imperial Shag
Imperial Shag
The Imperial Shag, Phalacrocorax atriceps, is a black and white cormorant native to many subantarctic islands, the Antarctic Peninsula and southern South America, primarily in rocky coastal regions, but locally also at large inland lakes. It is sometimes placed in the genus Leucocarbo instead...
(P. atriceps) complex, which occurs on the opposite end of the Earth from P. pelagicus. The supposed "cliff shag" subfamily Leucocarboninae is entirely paraphyletic cannot be accepted as originally circumscribed. If subfamilies are to be accepted in the Phalacrocoracidae, the Pelagic Shag and its relatives would go in the Phalacrocoracinae like most Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
cormorants and shags, while Leucocarboninae would include mainly Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...
taxa.
In fact, the correct genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
name for the Pelagic Cormorant, if Phalacrocorax is to be split up, would be Compsohalieus. This name would apply to the group around its type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
(Brandt's Cormorant
Brandt's Cormorant
The 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...
, P. penicillatus). This is a North Pacific clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
, which apart from Brandt's and the Pelagic Cormorant also includes the Red-faced Cormorant
Red-faced Cormorant
The Red-faced Cormorant, Red-faced Shag or Violet Shag, Phalacrocorax urile, is a species of cormorant that is found in the far north of the Pacific Ocean and Bering Sea, from the eastern tip of Hokkaidō in Japan, via the Kuril Islands, the southern tip of the Kamchatka Peninsula and the Aleutian...
(P. urile) and probably also the extinct Spectacled Cormorant
Spectacled Cormorant
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 Komandorski Islands and the nearby coast of Kamchatka...
(P. perspicillatus). They all have black feet, and in breeding plumage grow white filoplumes on the head and/or neck, and usually also two head-crests and white thigh
Thigh
In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...
patches like the present species does. They also share the back-thrown head during the "yawning" and the rapid wing-flutter in courtship display
Courtship display
Courtship display is a special, sometimes ritualised, set of behaviours which some animals perform as part of courtship. Courtship behaviours can include special calls, postures, and movements, and may involve special plumage, bright colours or other ornamentation. A good example is the 'dancing'...
. Among the Compsohalieus group, the Red-faced Cormorant is the sister species of P. pelagicus. Apart from loking almost alike, these two species also "yawn" many times in a row instead of giving the display just once, twist their bodies before taking flight during courtship, and the male and female post-landing calls are identical. The point-and-gargle response to threats is also an apomorphy of these two species.
Its traditional scientific name is the literal Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
ized Ancient Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
equivalent of the common name: Phalacrocorax is an ancient term for cormorants; literally, it means "bald raven
Raven
Raven is the common name given to several larger-bodied members of the genus Corvus—but in Europe and North America the Common Raven is normally implied...
", from falakrós (φᾶλακρός, "bald") + kórax (κόραξ, "raven"). pelagicus is – like the English loanword
Loanword
A loanword is a word borrowed from a donor language and incorporated into a recipient language. By contrast, a calque or loan translation is a related concept where the meaning or idiom is borrowed rather than the lexical item itself. The word loanword is itself a calque of the German Lehnwort,...
"pelagic" – derived from pelágios (πελᾶγιος, "of the open seas"). Compsohalieus, meanwhile, means "sleek fisher"; it derives from kompsós (κομψός, "elegant" or "sleek") + (h)alieus (ἇλιεύς, "fisherman").
Subspecies
Two subspeciesSubspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
are generally recognized. The difference between them is slight and generally agrees with Bergmann's Rule
Bergmann's Rule
Bergmann's rule is an ecogeographic principle that states that within a broadly distributed genus, species of larger size are found in colder environments, and species of smaller size are found in warmer regions. Although originally formulated in terms of species within a genus, it has often been...
:
- Phalacrocorax pelagicus pelagicus PallasPeter Simon PallasPeter Simon Pallas was a German zoologist and botanist who worked in Russia.- Life and work :Pallas was born in Berlin, the son of Professor of Surgery Simon Pallas. He studied with private tutors and took an interest in natural history, later attending the University of Halle and the University...
, 1811 – Northern Pelagic Cormorant. NW Pacific east to S AlaskaAlaskaAlaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
. The larger subspecies (but see below). - Phalacrocorax pelagicus resplendens AudubonJohn James AudubonJohn James Audubon was a French-American ornithologist, naturalist, and painter. He was notable for his expansive studies to document all types of American birds and for his detailed illustrations that depicted the birds in their natural habitats...
, 1838 – Southern Pelagic Cormorant. British ColumbiaBritish ColumbiaBritish Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
to NW MexicoMexicoThe United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. The smaller subspecies.
The Amchitka Cormorant or Kenyon's Shag (P. kenyoni) is a supposed species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
that was presumed to be closely related to the Pelagic Cormorant. It was described from the bones of three individuals snared in fishing nets in the late 1950s at Constantine Harbor
Constantine Harbor
Constantine Harbor is an inlet on the eastern end of the north coast of the island of Amchitka in the Aleutian Islands in Alaska. It is the site of an airport.-References:...
on Amchitka in the Aleutian Islands. The specific name kenyoni honors USFWS biologist
Biologist
A biologist is a scientist devoted to and producing results in biology through the study of life. Typically biologists study organisms and their relationship to their environment. Biologists involved in basic research attempt to discover underlying mechanisms that govern how organisms work...
Karl W. Kenyon, who collected the type specimen USNM 431164 on 22 February 1959. Some bones from prehistoric middens on Amchitka were also attributed to this taxon
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
. As distinctive cormorants were never seen alive in recent years on Amchitka, it was conjectured by some that Kenyon's Shag might have gone extinct in the 1960s-1970s (marine pollution
Marine pollution
Marine pollution occurs when harmful, or potentially harmful effects, can result from the entry into the ocean of chemicals, particles, industrial, agricultural and residential waste, noise, or the spread of invasive organisms. Most sources of marine pollution are land based...
and overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
would be possible reasons).
However, a subsequent analysis of a larger number of comparison specimens of the Pelagic Cormorant – mainly from birds that fell victim to the Exxon Valdez oil spill
Exxon Valdez oil spill
The Exxon Valdez oil spill occurred in Prince William Sound, Alaska, on March 24, 1989, when the Exxon Valdez, an oil tanker bound for Long Beach, California, struck Prince William Sound's Bligh Reef and spilled of crude oil. It is considered to be one of the most devastating human-caused...
– determined that the bones were attributable to small females of the latter species, and that their apparent distinctness was due to the original canonical analysis
Canonical analysis
In statistics, canonical analysis belongs to the family of regression methods for data analysis. Regression analysis quantifies a relationship between a predictor variable and a criterion variable by the coefficient of correlation r, coefficient of determination r², and the standard regression...
being distorted by insufficient specimens. The researchers also found that contrary to what was generally assumed, Pelagic Cormorants from the Aleutians were generally small birds – as opposed to western Alaskan individuals, which are usually very large. If the Aleutian population were to be considered a distinct subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
, the name kenyoni would apply. Verification of subspecies status would require DNA sequence
DNA sequence
The sequence or primary structure of a nucleic acid is the composition of atoms that make up the nucleic acid and the chemical bonds that bond those atoms. Because nucleic acids, such as DNA and RNA, are unbranched polymers, this specification is equivalent to specifying the sequence of...
analyses however, since the differences in morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
are not large and there is much variation between individuals.
On 20 July 2003, during an USFWS survey three small Pelagic Cormorants whose bills appeared to be red were noted at Karab Cove on Agattu Island. It may be that these were kenyoni, but whether the bill color distinguishes the presumed subspecies or whether it is due to a simple mutation
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
has not been determined. The large birds from the Prince William Sound
Prince William Sound
Prince William Sound is a sound off the Gulf of Alaska on the south coast of the U.S. state of Alaska. It is located on the east side of the Kenai Peninsula. Its largest port is Valdez, at the southern terminus of the Trans-Alaska Pipeline System...
region were formerly called P. p. robustus, but are not considered distinct today. Since there appear to be at least 2 recognizable and allopatric size groups in the northern subspecies alone, more research is clearly necessary.