Cormorant

• 1. Introduction

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  Cormorants are birds that seem to defy easy classification. They have webbed feet like ducks, dive like penguins, and carry a name derived from the Latin for "sea raven." From the shallow Li River in Guilin to the cliffs of subantarctic islands, from the pages of Homer's Odyssey to the hood ornaments of Packard automobiles, these birds have wound themselves through human culture for millennia. But what exactly is a cormorant? Why can no one agree on what to call them or how to count their species? And what does it mean that a bird capable of diving to 80 metres deep must still stand on a rock with its wings spread to dry? The family Phalacrocoracidae holds roughly 40 species, sorted now into seven genera by the International Ornithologists' Union following a 2021 consensus. The story of how scientists arrived at that number is almost as tangled as the birds themselves.

• 2. A Name Built on Confusion

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  "Cormorant" is almost certainly a contraction of the Latin corvus marinus, meaning "sea raven." In the early 19th century, the spelling "corvorant" still appeared in print, and the confusion ran deeper than etymology. The French explorer Andre Thevet wrote in 1558 that the beak of a cormorant resembled that of a raven or other corvid, a misidentification that shows the belief in a raven kinship persisted at least into the 16th century. In Germanic languages, the birds were simply called "sea ravens" until well after the Middle Ages.

  The split between "cormorant" and "shag" is no more systematic. Both names originally belonged to the two species found in Britain and Ireland: Phalacrocorax carbo, the great cormorant, and Gulosus aristotelis, the European shag. "Shag" referred to the bird's crest, conspicuous in the European shag and less so in the great cormorant. As English-speaking sailors spread across the globe and encountered new species, some birds got called cormorants and some shags, sometimes based on whether they had crests, sometimes not. In New Zealand, every species in the family is known locally as a shag, including four species called cormorants everywhere else in their range. In 1976, Gerard Frederick van Tets proposed a formal division that would tie the name "cormorant" to one genus and "shag" to another, but the proposal never caught on widely.

• 3. Built for the Deep

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  Imperial shags fitted with miniaturized video recorders have been filmed diving to depths of 80 metres to forage on the sea floor. That figure captures something essential about what makes the Phalacrocoracidae remarkable: they are supremely adapted to underwater pursuit, and their bodies show the compromises that adaptation demands.

  Cormorants and shags range in size from the pygmy cormorant at as little as 45 cm and 340 grams to the flightless cormorant at up to 100 cm and 5 kg. The recently extinct spectacled cormorant averaged 6.3 kg, making it rather larger still. All of them share a long, thin, sharply hooked bill and feet webbed between all four toes. They propel themselves underwater primarily with their feet, though some species also use their wings. The trade-off is significant: relatively short wings keep underwater movement efficient, but they leave cormorants with among the highest flight costs of any flying bird.

  After fishing, cormorants go ashore and hold their wings out in the sun in a posture widely associated with the birds. Whether this serves primarily to dry the feathers remains a matter of debate. Some sources hold that the outer plumage absorbs water but keeps the layer of air next to the skin dry. A detailed study of the great cormorant concluded that wing-spreading does dry the plumage, but other functions have been proposed: thermoregulation, digestion, balance, or signalling the presence of fish. Notably, the flightless cormorant spreads its wings in this posture even though it cannot fly, while Antarctic shags and red-legged cormorants do not adopt it at all.

• 4. Ancient Bones, Uncertain Lineage

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  A scapula found in the Nemegt Formation in Mongolia, now held in the PIN collection, dates to roughly 70 million years ago and has been proposed as a cormorant fossil. A right femur from the Lance Formation near Lance Creek, Wyoming, catalogued as AMNH FR 25272 and dating to the Maastrichtian stage of the Late Cretaceous around 66 million years ago, has been suggested as the second-oldest record of the family. Scientists now believe these are likely misidentifications.

  The best current reading of the evidence is that the family Phalacrocoracidae diverged from its closest relatives during the Early Oligocene, perhaps around 30 million years ago. Phylogenetic evidence indicates that the cormorants split from the darters specifically during the Late Oligocene. The closest living relatives of cormorants and shags are the darters and the Sulidae, meaning gannets and boobies, all of which have a primarily Gondwanan distribution.

  Two genera of prehistoric cormorants are now widely accepted: Limicorallus, from the middle Oligocene of Chelkar-Teniz in Kazakhstan, and Nectornis, from the Late Oligocene and Early Miocene of Central Europe through the Middle Miocene of Bes-Konak in Turkey. Limicorallus was initially described by some researchers as a rail or a dabbling duck. Undescribed remains from the Quercy Phosphorites of France date to sometime between the Late Eocene and the mid-Oligocene. A working hypothesis suggests that the first modern cormorants were small freshwater species from eastern, south-eastern, or southern Asia, dispersing as tectonic events reshaped the Eurasian landmass.

• 5. Classifying the Ungovernable

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  A multigene molecular phylogenetic study published in 2014 proposed a seven-genera treatment of the family, which the IUCN Red List and BirdLife International adopted and the IOC followed in 2021. Before that, the IOC had grouped all but Microcarbo and Leucocarbo into a single broad Phalacrocorax, an arrangement that made that genus deeply paraphyletic with respect to Leucocarbo. The Clements Checklist had recognized only Microcarbo as separate.

  The genus name Phalacrocorax is Latinized Ancient Greek combining phalakros, meaning "bald," and korax, meaning "raven." This is thought to refer either to the ornamental white head plumes found in Mediterranean birds or the creamy white cheek patches of adult great cormorants, though neither feature is universal across the family. The unique shared anatomy of cormorants and darters includes a bone at the back of the top of the skull called the os nuchale or occipital style, which provides anchorage for the muscles that close the lower jaw with force. This bone, and the highly developed muscle group designated M. adductor mandibulae caput nuchale, are found only in the families Phalacrocoracidae and Anhingidae.

  Several evolutionary groupings remain contested. The cliff shags form what appears to be a convergent paraphyletic group. The mtDNA sequence data from the 12S rRNA and ATPase subunits six and eight cannot resolve several groups satisfactorily; many species remain unsampled, the fossil record has not been integrated, and the effects of hybridization, known in some Pacific species, have not been studied in detail as of 2022.

• 6. Fishing with Birds

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  Archaeological evidence places cormorant fishing in Ancient Egypt, Peru, Korea, and India. The practice reached its greatest scale in China and Japan, where in some areas it became a commercial enterprise. In Japan, cormorant fishing is called ukai, and the fisherman who performs it is known as an usho. Traditional ukai has continued without interruption for 1,300 years on the Nagara River in the city of Gifu, in Gifu Prefecture. A similar tradition survives in the city of Inuyama in Aichi. In Guilin, in Guangxi province, cormorants fish the shallow Li River. Japanese fishermen use the Japanese cormorant, Phalacrocorax capillatus; Chinese fishermen commonly use the great cormorant, Phalacrocorax carbo. In Europe, a comparable practice was used on Doiran Lake in the region of Macedonia, and James VI and I appointed a keeper of cormorants named John Wood and built ponds at Westminster to train the birds to fish.

  The technique involves tying a snare near the base of the bird's throat. Small fish pass through, but a large fish lodges in the throat and is retrieved by the fisherman when the bird returns to the raft. The practice has declined as more efficient fishing methods have developed, though it survives as cultural tradition. In Japan, environmental pressures now threaten even that survival: reduced numbers of the ayu river fish, on which ukai depends, put the tradition at risk.

• 7. In Myth, Literature, and Culture

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  In Homer's Odyssey, cormorants nest on the isle of Calypso alongside owls and falcons, and the god Hermes is compared to a cormorant as he arrives to command Calypso to release Odysseus. Scholars have suggested the bird may also function in the poem as a symbol of death and decay, partly through its association with cypress trees.

  In Paradise Lost, Satan assumes the form of a cormorant during his first intrusion into the Garden of Eden, embodying greed. In some Scandinavian traditions, cormorants carry spirits of those lost at sea who return to visit their loved ones. The Norwegian municipalities of Rost, Loppa, and Skjervoy each include a cormorant in their coat of arms. The symbolic liver bird of Liverpool is commonly thought to be a cross between an eagle and a cormorant.

  In 1853, a woman was found on San Nicolas Island, off the southern coast of California, wearing a dress made from cormorant feathers sewn together with whale sinews. She had lived alone on the island for 18 years. Later baptised "Juana Maria," her original name was lost. She brought the green cormorant dress with her when removed from the island; that dress is reported to have ended up at the Vatican. Her story was fictionalized in the children's novel Island of the Blue Dolphins.

  Charlotte Bronte's Jane Eyre includes one of the fictional paintings Jane creates, in which a cormorant sits on a half-submerged mast holding a gold bracelet set with gems, representing the character Blanche Ingram. In the Sherlock Holmes story "The Adventure of the Veiled Lodger," Dr. Watson invokes "the politician, the lighthouse, and the trained cormorant" as a threat to release a suppressed case if his notes are tampered with. The cormorant also served as the hood ornament for the Packard automobile brand and was chosen as the emblem of the Ministry of Defence Joint Services Command and Staff College at Shrivenham, where its qualities of flight, sea fishing, and land nesting were seen as fitting symbols for a college unifying the Army, Navy, and Royal Air Force.