Phalacrocoracidae is afamily of approximately 40species ofaquatic birds commonly known ascormorants andshags. Several different classifications of the family have been proposed, but in 2021 theInternational Ornithologists' Union (IOU) adopted a consensus taxonomy of sevengenera.[1] Thegreat cormorant (Phalacrocorax carbo) and thecommon shag (Gulosus aristotelis) are the only two species of the family commonly encountered in Britain and Ireland,[2] and the names "cormorant" and "shag" have been later assigned to different species in the family somewhat haphazardly.
Cormorants and shags are medium-to-large birds, with body weight in the range of 0.35–5 kilograms (0.77–11.02 lb) and wing span of 60–100 centimetres (24–39 in). The majority of species have dark feathers. The bill is long, thin and hooked. Their feet have webbing between all four toes. All species are fish-eaters, catching the prey by diving from the surface. They are excellent divers, and under water they propel themselves with their feet with help from their wings; some cormorant species have been found to dive as deep as 45 metres (150 ft). Cormorants and shags have relatively short wings due to their need for economical movement underwater, and consequently have among the highest flight costs of any flying bird.[3]
Cormorants nest in colonies around the shore, on trees, islets or cliffs. They are coastal rather than oceanic birds, and some have colonised inland waters. The original ancestor of cormorants seems to have been a freshwater bird.[citation needed] They range around the world, except for the central Pacific islands.
Cormorants might have been a freshwater species from south Asia. From there, they spread around the Eurasian landmass and the world.[4]
"Cormorant" is acontraction probably derived from Latincorvus marinus, "searaven"; in the early 19th century, the similarly derived spelling "corvorant" was sometimes used.[5]Cormoran is theCornish name of the sea giant in the tale ofJack the Giant Killer. Indeed, "sea raven" or analogous terms were the usual terms for cormorants inGermanic languages until after theMiddle Ages. The French explorerAndré Thévet commented in 1558: "the beak [is] similar to that of a cormorant or other corvid", which demonstrates that the erroneous belief that the birds were related to ravens lasted at least to the 16th century.
No consistent distinction exists between cormorants and shags. The names "cormorant" and "shag" were originally the common names of the two species of the family found inIreland and also inGreat Britain – Phalacrocorax carbo (now referred to by ornithologists as thegreat cormorant) andGulosus aristotelis (theEuropean shag). "Shag" refers to the bird's crest, which is conspicuous in the European shag, but less so in the great cormorant. As other species were encountered byEnglish-speaking sailors and explorers elsewhere in the world, some were called cormorants and some shags, sometimes depending on whether they had crests or not. Sometimes the same species is called a cormorant in one part of the world and a shag in another; for example, all species in the family which occur inNew Zealand are known locally as shags, including four non-endemic species known as cormorant elsewhere in their range.[citation needed] In 1976,Gerard Frederick van Tets proposed to divide the family into twogenera and attach the name "cormorant" to one and "shag" to the other,[6] but this nomenclature has not been widely adopted.[citation needed]
Great cormorant with hooked billLittle cormorant with wings spread
Cormorants and shags are medium-to-largeseabirds. They range in size from thepygmy cormorant (Microcarbo pygmaeus), at as little as 45 cm (18 in) and 340 g (12 oz), to theflightless cormorant (Nannopterum harrisi), at a maximum size 100 cm (39 in) and 5 kg (11 lb). The recently extinctspectacled cormorant (Urile perspicillatus) was rather larger, at an average size of 6.3 kg (14 lb). Nearly all the Northern Hemisphere species have mainly darkplumage, but many Southern Hemisphere species are black and white, and a few (e.g. thespotted shag of New Zealand) are quite colourful. Many species have areas of coloured skin on the face (thelores and thegular skin) which can be bright blue, orange, red or yellow, typically becoming more brightly coloured in the breeding season. The bill is long, thin, and sharply hooked. Their feet have webbing between all four toes, as in their relatives.
Habitat varies from species to species: some are restricted to seacoasts, while others occur in both coastal and inland waters to varying degrees. They range around the world, except for the central Pacific islands.
All cormorants and shags are fish-eaters, dining on smalleels, fish, and even water snakes. They dive from the surface, though many species make a characteristic half-jump as they dive, presumably to give themselves a more streamlined entry into the water. Under water they propel themselves with their feet, though some also propel themselves with their wings (see the picture,[7] commentary,[8] and existing reference video[9]). Imperial shags fitted with miniaturized video recorders have been filmed diving to depths of as much as 80 metres (260 ft) to forage on the sea floor.[10]
Wing-drying behaviour in a little cormorant
After fishing, cormorants go ashore, and are frequently seen holding their wings out in the sun. All cormorants havepreen gland secretions that are used ostensibly to keep the feathers waterproof. Some sources[11] state that cormorants have waterproof feathers while others say that they have water-permeable feathers.[12][13] Still others suggest that the outer plumage absorbs water but does not permit it to penetrate the layer of air next to the skin.[14] The wing drying action is seen even in the flightless cormorant but not in the Antarctic shags[15] or red-legged cormorants. Alternate functions suggested for the spread-wing posture include that it aidsthermoregulation[16] or digestion, balances the bird, or indicates presence of fish. A detailed study of the great cormorant concluded there is little doubt that it serves to dry the plumage.[17][18][19]
Cormorants are colonial nesters, using trees, rocky islets, or cliffs. Theeggs are a chalky-blue colour. There is usually one brood a year. Parentsregurgitate food to feed their young.
This section needs to beupdated. The reason given is: several paragraphs ("The cormorant family are...", "Several evolutionary groups are...", and all but the last sentence of "In recent years, three...") appear to have been written in the mid-2000s and minimally updated since then, and as such are highly outdated, requiring extensive revision to reflect a modern state of knowledge of the relationships of cormorants and their relatives. Please help update this article to reflect recent events or newly available information.(June 2023)
The genusPhalacrocorax, from which thefamily name Phalacrocoracidae is derived, isLatinised fromAncient Greekφαλακρόςphalakros "bald" andκόραξkorax "raven".[20] This is thought to refer to the ornamental white head plumes prominent in Mediterranean birds of this species, or the creamy white patch on the cheeks of adultgreat cormorants, but is certainly not a unifying characteristic of cormorants.
The cormorant family was traditionally placed within thePelecaniformes or, in theSibley–Ahlquist taxonomy of the 1990s, the expandedCiconiiformes. Pelecaniformes in the traditional sense—all waterbird groups withtotipalmate foot webbing—are not amonophyletic group, even after the removal of the distantly-relatedtropicbirds. Their relationships and delimitation – apart from being part of a "higher waterfowl"clade which is similar but not identical to Sibley and Ahlquist's "pan-Ciconiiformes" – remain mostly unresolved. Notwithstanding, all evidence agrees that the cormorants and shags are closer to thedarters andSulidae (gannets and boobies), and perhaps the pelicans or evenpenguins, than to all other living birds.[21]
In recent years, three preferred treatments of the cormorant family have emerged: either to leave all living cormorants in a single genus,Phalacrocorax, or to split off a few species such as theimperial shag complex (inLeucocarbo) and perhaps theflightless cormorant. Alternatively, the genus may be disassembled altogether and in the most extreme case be reduced to thegreat,white-breasted andJapanese cormorants.[22] In 2014, a landmark study proposed a 7 genera treatment, which was adopted by theIUCN Red List andBirdLife International, and later by theIOC in 2021, standardizing it.[1][23]
The cormorants and the darters have a unique bone on the back of the top of the skull known as theos nuchale or occipital style which was called a xiphoid process in early literature. This bony projection provides anchorage for the muscles that increase the force with which the lower mandible is closed.[5][24] This bone and the highly developed muscles over it, the M. adductor mandibulae caput nuchale, are unique to the families Phalacrocoracidae and Anhingidae.[25][26]
Severalevolutionary groups are still recognizable. However, combining the available evidence suggests that there has also been a great deal ofconvergent evolution; for example, the cliff shags are a convergentparaphyletic group. The proposed division intoPhalacrocorax sensu stricto (orsubfamily "Phalacrocoracinae") cormorants andLeucocarbo sensu lato (or "Leucocarboninae") shags[6][27] does have some degree of merit.[28] The resolution provided by themtDNA12S rRNA andATPasesubunits six and eightsequence data[28] is not sufficient to resolve several groups to satisfaction properly; in addition, many species remain unsampled, the fossil record has not been integrated in the data, and the effects of hybridisation – known in some Pacific species especially – on the DNA sequence data are unstudied.
Around Indian Ocean, one species extending from Central Asia into Europe. Mostly in freshwater habitat. Small (about 50–60 cm long), nondescript black to dark brown (except for one species with white underparts).
Subtropical to subantarctic Pacific South America, ranging a bit into the southwestern Atlantic. Maritime. Mid-sized (around 75 cm), grey with scalloped wings and contrasting white/yellow/red neck mark and bare parts. Its high-pitched chirping calls are quite unlike those of other cormorants.
Northern Pacific, one species extending into subtropical waters on the American West Coast. Maritime. Smallish to large (65–100 cm), generally black with metallic sheen (usually blue/green), in breeding plumage with bright bare facial skin in the eye region and two crests (crown and nape).
Mostly around the Indian Ocean, one species group extending throughout Eurasia and to Atlantic North America. Maritime to freshwater. Size very variable (60–100 cm), blackish with metallic sheen (usually bronze to purple) and/or white cheek and thigh patches or underside at least in breeding plumage; usually a patch of bare yellow skin at the base of the bill.
Breeds in the European Arctic, winters in Europe and North Africa. Maritime. Mid-sized (70–80 cm), glossy black, in breeding plumage with a forehead crest curled to the front.
Throughout the Americas. Mostly freshwater. Smallish to large (65–100 cm), nondescript brownish-black. One species with white tufts on sides of head in breeding plumage.
Generally Subantarctic, but extending farther north in South America; many oceanic-island endemics. Maritime. Smallish to largish (65–80 cm), typically black above and white below, and with bare yellow or red skin in the facial region. A southern circumpolar group of several species (the blue-eyed shag complex) is characterised by bright blue orbital skin.
Prior to 2021, the IOU (or formerly the IOC) classified all these species in just three genera:Microcarbo,Leucocarbo, and a broadPhalacrocorax containing all remaining species; however, this treatment renderedPhalacrocorax deeply paraphyletic with respect toLeucocarbo. Other authorities, such as theClements Checklist, formerly recognised onlyMicrocarbo as a separate genus fromPhalacrocorax.
The details of the evolution of the cormorants are mostly unknown. Even the technique of using the distribution and relationships of a species to figure out where it came from, biogeography, usually very informative, does not give very specific data for this probably rather ancient and widespread group. However, the closest living relatives of the cormorants and shags are the other families of thesuborderSulae—darters andgannets and boobies—which have a primarilyGondwanan distribution. Hence, at least the modern diversity of Sulae probably originated in the southern hemisphere.
While the Leucocarbonines are almost certainly of southern Pacific origin—possibly even the Antarctic which, at the time when cormorants evolved, was not yet ice-covered—all that can be said about the Phalacrocoracines is that they are most diverse in the regions bordering the Indian Ocean, but generally occur over a large area.
Similarly, the origin of the family is shrouded in uncertainties. SomeLate Cretaceous fossils have been proposed to belong with the Phalacrocoracidae: Ascapula from theCampanian-Maastrichtian boundary, about 70 mya (million years ago), was found in theNemegt Formation in Mongolia; it is now in thePIN collection.[29] It is from a bird roughly the size of a spectacled cormorant, and quite similar to the corresponding bone inPhalacrocorax. AMaastrichtian (Late Cretaceous, c. 66 mya) rightfemur,AMNH FR 25272 from theLance Formation nearLance Creek, Wyoming, is sometimes suggested to be the second-oldest record of the Phalacrocoracidae; this was from a rather smaller bird, about the size of along-tailed cormorant.[30] However, cormorants likely originated much later, and these are likely misidentifications.[31]
As theEarly Oligocene"Sula" ronzoni cannot be assigned to any of the sulid families—cormorants and shags, darters, and gannets and boobies—with certainty, the best interpretation is that the Phalacrocoracidae diverged from their closest ancestors in the Early Oligocene, perhaps some 30 million years ago, and that the Cretaceous fossils represent ancestral sulids, "pelecaniforms" or "higher waterbirds"; at least the last lineage is generally believed to have been already distinct and undergoingevolutionary radiation at theend of the Cretaceous. What can be said with near certainty is that AMNH FR 25272 is from a diving bird that used its feet for underwater locomotion; as this is liable to result in some degree of convergent evolution and the bone is missing indisputable neornithine features, it is not entirely certain that the bone is correctly referred to this group.[32]
Phylogenetic evidence indicates that the cormorants diverged from their closest relatives, the darters, during the Late Oligocene, indicating that most of the claims of Cretaceous or early Paleogene cormorant occurrences are likely misidentifications.[31]
During the late Paleogene, when the family presumably originated, much of Eurasia was covered by shallow seas, as theIndian Plate finally attached to the mainland. Lacking a detailed study, it may well be that the first "modern" cormorants were small species from eastern, south-eastern or southern Asia, possibly living in freshwater habitat, that dispersed due totectonic events. Such a scenario would account for the present-day distribution of cormorants and shags and is not contradicted by the fossil record; as remarked above, a thorough review of the problem is not yet available.
Double-crested cormorant
Even whenPhalacrocorax was used to unite all living species, two distinct genera of prehistoric cormorants became widely accepted today:
Limicorallus (Indricotherium middle Oligocene of Chelkar-Teniz, Kazakhstan)
Nectornis (Late Oligocene/Early Miocene of Central Europe – Middle Miocene of Bes-Konak, Turkey) – includesOligocorax miocaenus
The proposed genusOligocorax appears to beparaphyletic; the European species have been separated inNectornis, and the North American ones placed in the expandedPhalacrocorax; the latter might just as well be included inNannopterum. ALate Oligocene fossil cormorant foot fromEnspel, Germany, sometimes placed inOligocorax, would then be referable toNectornis if it proves not to be too distinct.Limicorallus, meanwhile, was initially believed to be arail or adabbling duck by some. There are also undescribed remains of apparent cormorants from theQuercy Phosphorites ofQuercy (France), dating to some time between theLate Eocene and the mid-Oligocene. All these early European species might belong to the basal group of "microcormorants", as they conform with them in size and seem to have inhabited the same habitat: subtropical coastal or inland waters. While this need not be more thanconvergence, the phylogeny of the modern (sub)genusMicrocarbo – namely, whether the Western EurasianM. pygmaeus is abasal or highly derived member of its clade – is still not well understood at all as of 2022.
Some other Paleogene remains are sometimes assigned to the Phalacrocoracidae, but these birds seem rather intermediate between cormorants and darters (and lack clearautapomorphies of either). Thus, they may be quite basal members of thePalacrocoracoidea. Thetaxa in question are:
The remaining fossil species are not usually placed in a modern phylogenetic framework. While the numerous western US species are most likely prehistoric representatives of the coastalUrile or inlandNannopterum, the European fossils pose much more of a problem due to the singularcommon shag being intermediate in size between the other two European cormorant lineages, and as of 2022 still ofmysterious ancestry; notably, a presumably lost collection of Late Miocene fossils from theOdesa region may have contained remains of all three (sub)genera inhabiting Europe today. Similarly, the Plio-Pleistocene fossils from Florida have been allied withNannopterum and evenUrile, but may conceivably bePhalacrocorax; they are in serious need of revision since it is not even clear how many species are involved. Provisionally, the fossil species are thus all placed inPhalacrocorax here:
Phalacrocorax marinavis (Oligocene – Early Miocene of Oregon, US) – formerlyOligocorax;Urile orNannopterum?
Phalacrocorax littoralis (Late Oligocene/Early Miocene of St-Gérand-le-Puy, France) – formerlyOligocorax;Nectornis?
Phalacrocorax intermedius (Early – Middle Miocene of C Europe) – includesP. praecarbo, Ardea/P. brunhuberi andBotaurites avitus;Microcarbo,Phalacrocorax orGulosus?
Phalacrocorax ibericus (Late Miocene of Valles de Fuentiduena, Spain) –Microcarbo,Phalacrocorax orGulosus?
Phalacrocorax lautus (Late Miocene of Golboçica, Moldavia) –Microcarbo,Phalacrocorax orGulosus?
Phalacrocorax serdicensis (Late Miocene of Hrabarsko, Bulgaria);Microcarbo,Phalacrocorax orGulosus?
Phalacrocorax sp(p). (Late Miocene of Odesa region, Ukraine) – up to 4 species, one of which is probablyP. longipes;Microcarbo,Phalacrocorax and/orGulosus?[33]
Phalacrocorax femoralis (Modelo Late Miocene/Early Pliocene of WC North America) – formerlyMiocorax;Nannopterum?
Phalacrocorax sp. (Late Miocene/Early Pliocene of Lee Creek Mine, US) –Nannopterum orPhalacrocorax?
Phalacrocorax sp. 1 (Late Miocene/Early Pliocene of WC South America) – probablyLeucocarbo
Phalacrocorax sp. 2 (Pisco Late Miocene/Early Pliocene of SW Peru) –Poikilocarbo orLeucocarbo?
Phalacrocorax longipes (Late Miocene – Early Pliocene of Ukraine) – formerlyPliocarbo;Microcarbo,Phalacrocorax orGulosus?
Phalacrocorax goletensis (Early Pliocene – Early Pleistocene of Mexico) –Urile orNannopterum, perhapsPoikilocarbo orLeuocarbo
Phalacrocorax wetmorei (Bone Valley Early Pliocene of Florida) –Nannopterum orPhalacrocorax?
Phalacrocorax sp. (Bone Valley Early Pliocene of Polk County, Florida, US) –Nannopterum orPhalacrocorax?[34]
Phalacrocorax leptopus (Juntura Early/Middle Pliocene ofJuntura,Malheur County, Oregon, US) –Nannopterum?
Phalacrocorax reliquus (Middle Pliocene of Mongolia) –Microcarbo,Phalacrocorax orGulosus?
Phalacrocorax idahensis (Middle Pliocene – Pleistocene of Idaho, US, and possibly Florida) –Nannopterum?
Phalacrocorax destefanii[verification needed] (Late Pliocene of Italy) – formerlyParacorax;Microcarbo,Phalacrocorax orGulosus?
Phalacrocorax filyawi (Pinecrest Late Pliocene of Florida, US) – may beP. idahensis;Nannopterum orPhalacrocorax, perhapsUrile?
Phalacrocorax kennelli (San Diego Late Pliocene of California, US) –Urile orNannopterum?
Phalacrocorax kumeyaay (San Diego Late Pliocene of California, US) –Urile orNannopterum?
Phalacrocorax macer (Late Pliocene of Idaho, US) –Nannopterum?
Phalacrocorax mongoliensis (Late Pliocene of W Mongolia) –Microcarbo,Phalacrocorax orGulosus?
Phalacrocorax sp. (La Portada Late Pliocene of N Chile) – may be same as Late Miocene/Early Pliocene "Phalacrocorax sp. 2";Poikilocarbo orLeucocarbo?
Phalacrocorax rogersi (Late Pliocene – Early Pleistocene of California, US) –Urile orNannopterum?
Phalacrocorax gregorii (Late Pleistocene of Australia) – possibly not a valid species;Microcarbo,Phalacrocorax orLeucocarbo?
Phalacrocorax vetustus (Late Pleistocene of Australia) – formerlyAustralocorax, possibly not a valid species;Microcarbo,Phalacrocorax orLeucocarbo?
Phalacrocorax sp. (Sarasota County, Florida, US) – may beP. filawyi/idahensis;Nannopterum orPhalacrocorax?
The former"Phalacrocorax" (or"Oligocorax")mediterraneus is now considered to belong to thebathornithidParacrax antiqua.[35]"P." subvolans was actually a darter (Anhinga).
Cormorant culling is the intentional killing of cormorants by humans for the purposes ofwildlife management. It has been practiced for centuries, with supporters of culling generally arising from theangling community. Culling techniques may involve the killing of birds, the destruction of eggs, or both. Historically, culls have occurred to protect the interests of recreational and commercial fishermen who perceive the animals to be competing with them for their intended catch or for the prey of their intended catch. Since the 1960s, the growingaquaculture industry has undertaken cormorant culls to protect its farmed fish and crustacean stocks. Opponents of cormorant culling include conservation groups such as theNational Audubon Society, Cormorant Defenders International[36] andSea Shepherd.[37]
Humans have used cormorants' fishing skills in various places in the world. Archaeological evidence suggests that cormorant fishing was practised in Ancient Egypt, Peru, Korea and India, but the strongest tradition has remained in China and Japan, where it reached commercial-scale level in some areas.[38] In Japan, cormorant fishing is calledukai (鵜飼) and is performed by a fisherman known as anusho.[39] Traditional forms ofukai can be seen on theNagara River in the city ofGifu,Gifu Prefecture, wherecormorant fishing has continued uninterrupted for 1300 years, or in the city ofInuyama,Aichi. InGuilin,Guangxi, cormorants are famous for fishing on the shallowLi River. In Gifu, theJapanese cormorant (P. capillatus) is used; Chinese fishermen often employgreat cormorants (P. carbo).[40] In Europe, a similar practice was also used onDoiran Lake in theregion of Macedonia.[41]James VI and I appointed a keeper of cormorants,John Wood, and built ponds atWestminster to train the birds to fish.[42]
In a common technique, a snare is tied near the base of the bird's throat, which allows the bird only to swallow small fish. When the bird captures and tries to swallow a large fish, the fish is caught in the bird's throat. When the bird returns to the fisherman's raft, the fisherman helps the bird to remove the fish from its throat. The method is not as common today, since more efficient methods of catching fish have been developed, but is still practised as a cultural tradition.[40][38]
In Japan, environmental changes threaten traditionalukai because of reduced numbers of theayu river fish that cormorants are used to catch.[39]
Cormorants feature inheraldry and medieval ornamentation, usually in their "wing-drying" pose, which was seen as representing the Christian cross, and symbolizing nobility and sacrifice. InParadise Lost,Satan assumes the form of a cormorant during his first intrusion into theGarden of Eden, representing greed.[43]
In some Scandinavian areas, they are considered good omen; in particular, in Norwegian tradition spirits of those lost at sea come to visit their loved ones disguised as cormorants.[43] For example, the Norwegian municipalities ofRøst,Loppa andSkjervøy have cormorants in their coat of arms. The symbolicliver bird of Liverpool is commonly thought to be a cross between an eagle and a cormorant.
In Homer's epic poem The Odyssey, the isle of the sea-nymph Calypso is described as having cormorants present alongside owls and falcons, and Hermes is likened to a cormorant when he arrives to command the nymph Calypso to let Odysseus return home.[44] McCullagh suggests that the cormorant, associated with cypress trees, might act in part as a symbol of death and decay in the text.[45]
In 1853, a woman wearing a dress made of cormorant feathers was found onSan Nicolas Island, off the southern coast ofCalifornia. She had sewn the feather dress together using whale sinews. She is known as the Lone Woman of San Nicolas and was later baptised "Juana Maria" (her original name is lost). The woman had lived alone on the island for 18 years before being rescued. When removed from San Nicolas, she brought with her a green cormorant dress she made; this dress is reported to have been removed to the Vatican.[citation needed] Juana Maria's story was fictionalized in the children's novelIsland of the Blue Dolphins.
The bird has inspired numerous writers, includingAmy Clampitt, who wrote apoem called "The Cormorant in its Element". The species she described may have been thepelagic cormorant, which is the only species in the temperate U.S. with the "slim head ... vermilion-strapped" and "big black feet" that she mentions.[citation needed]
One gleam of light lifted into relief a half-submerged mast, on which sat a cormorant, dark and large, with wings flecked with foam; its beak held a gold bracelet, set with gems, that I had touched with as brilliant tints as my palette could yield, and as glittering distinctness as my pencil could impart.
In theSherlock Holmes story "The Adventure of the Veiled Lodger",Dr. Watson warns that if there are further attempts to get at and destroy his private notes regarding his time withSherlock Holmes, "the whole story concerning the politician, the lighthouse, and the trained cormorant will be given to the public. There is at least one reader who will understand."
The cormorant was chosen as the emblem for the Ministry of DefenceJoint Services Command and Staff College at Shrivenham. A bird famed for flight, sea fishing and land nesting was felt to be particularly appropriate for a college that unified leadership training and development for the Army, Navy and Royal Air Force.[citation needed]
After a member produced a mock magazine cover from a photograph of roosting cormorants, the bird became the unofficial mascot of the Pentax Discuss Mailing List with many posts dedicated to discussion of the photography of the species.[48]
Stephen Gregory’s 1987 horror novelThe Cormorant concerns a man who inherits both a cottage and a cormorant from his late uncle. The 1993 film adaptation starsRalph Fiennes and is directed by Peter Markham.
^Marchant S. M.; Higgins, P. J. (1990).Handbook of Australian, New Zealand and Antarctic Birds. Vol 1A. Oxford University Press.
^Hennemann, W. W., III (1984). "Spread-winged behaviour of double-crested and flightless cormorantsPhalacrocorax auritus andP. harrisi: wing drying or thermoregulation?".Ibis.126 (2):230–239.doi:10.1111/j.1474-919X.1984.tb08002.x.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^Cook, Timothee R.; Leblanc, Guillaume (September 2007). "Why is wing-spreading behaviour absent in blue-eyed shags?".Animal Behaviour.74 (3):649–652.doi:10.1016/j.anbehav.2006.11.024.
^Curry-Lindahl, Kai (1970). "Spread-Wing Postures in Pelecaniformes and Ciconiiformes".The Auk.87 (2):371–372.doi:10.2307/4083936.JSTOR4083936.
^These are the fossils described in the same paper asPelecanus odessanus and sometimes cited as "Phalacrocorax sp. Wildhalm", which is a widespreadlapsus calami or printing error for the initial describer, Ignatiy Vidgal'm (Игнатий Видгальм in Russian, a German emigrant originally named Ignaz Wi(e)dhalm and often transcribed as "J. Widhalm"). He discussed three presumed species of cormorant under the provisional non-Linnean names "Haliaeus fossilis, var. Odessana major, medius, [a]nd minor" ("fossil cormorant, large/mid-sized/small Odessan variety"). While various different bones were assigned to the large species (and eventually referred toP. longipes), one small and one mid-sized tarsometatarsus fragment remained unassigned; a few proximal ends of the same bone were provisionally included in the large species, but exceed its more complete tarsometatarsi in size and may represent a distinct and even larger fourth species. The fossils are probably lost nowadays and even the original publication is held by very few libraries; this has so far prevented a thorough review of the remains, but one partialcoracoid does not appear to belong toPhalacrocoraxsensu stricto and may have been closer inhabitus to North Pacific shags (Urile), but is unlikely to have been closely related[verification needed] to these: Howard (1932).
^Aproximalulna, Specimen PB 311,Pierce Brodkorb collection. Initially assigned toP. idahensis. However, it is far too large, being from a very big species possibly larger than a great cormorant: Murray (1970).
^James Edmund Harting,The Ornithology of Shakespeare (London, 1871), p. 262: Frederick Devon,Issues of the Exchequer (London, 1836), pp. 333–5.
^abMurphy-Hiscock, Arin (2012).Birds - A Spiritual Field Guide: Explore the Symbology and Significance of These Divine Winged Messengers. Adams Media. pp. 48–49.ISBN978-1-4405-2688-6.
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