An auk or alcid is a

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

of the family Alcidae in the order

Charadriiformes Charadriiformes (, from ''Charadrius'', the type genus of family Charadriidae) is a diverse order of small to medium-large birds. It includes about 390 species and has members in all parts of the world. Most charadriiform birds live near water a ...

. The alcid family includes the murres,

guillemot Guillemot is the common name for several species of seabird in the Alcidae or auk family (part of the order Charadriiformes). In British use, the term comprises two genera: ''Uria'' and ''Cepphus''. In North America the ''Uria'' species are ...

s, auklets,

puffin Puffins are any of three species of small alcids (auks) in the bird genus ''Fratercula''. These are pelagic seabirds that feed primarily by diving in the water. They breed in large colonies on coastal cliffs or offshore islands, nesting in crev ...

s, and murrelets. The word "auk" is derived from Icelandic ''álka'', from

Old Norse Old Norse, Old Nordic, or Old Scandinavian, is a stage of development of North Germanic dialects before their final divergence into separate Nordic languages. Old Norse was spoken by inhabitants of Scandinavia and their overseas settlement ...

''alka'' (auk), from

Proto-Germanic Proto-Germanic (abbreviated PGmc; also called Common Germanic) is the reconstructed proto-language of the Germanic branch of the Indo-European languages. Proto-Germanic eventually developed from pre-Proto-Germanic into three Germanic br ...

*''alkǭ'' (sea-bird, auk). The family contains 25 extant or recently extinct species that are divided into 11 genera. Apart from the extinct

great auk The great auk (''Pinguinus impennis'') is a species of flightless alcid that became extinct in the mid-19th century. It was the only modern species in the genus ''Pinguinus''. It is not closely related to the birds now known as penguins, wh ...

, all auks can fly, and are excellent swimmers (appearing to "fly") and divers, but their walking appears clumsy. Several species have different English names in Europe and North America. The two species known as murres in North America are called guillemots in Europe, and the species called little auk in Europe is referred to as dovekie in North America.

Description

Auks are superficially similar to

penguin Penguins (order Sphenisciformes , family Spheniscidae ) are a group of aquatic flightless birds. They live almost exclusively in the Southern Hemisphere: only one species, the Galápagos penguin, is found north of the Equator. Highly adap ...

s, having black-and-white colours, upright posture, and some of their habits. Nevertheless, they are not closely related to penguins, but rather are believed to be an example of moderate

convergent evolution Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

. Auks are monomorphic (males and females are similar in appearance). Extant auks range in size from the least auklet, at 85 g (3 oz) and , to the

thick-billed murre The thick-billed murre or Brünnich's guillemot (''Uria lomvia'') is a bird in the auk family (Alcidae). This bird is named after the Danish zoologist Morten Thrane Brünnich. The very deeply black North Pacific subspecies ''Uria lomvia arra ...

, at and . Due to their short wings, auks have to flap their wings very quickly to fly. Although not to the extent of penguins, auks have largely sacrificed flight, and also mobility on land, in exchange for swimming ability; their wings are a compromise between the best possible design for diving and the bare minimum needed for flying. This varies by subfamily, with the ''Uria'' guillemots (including the

razorbill The razorbill, razor-billed auk, or lesser auk (''Alca torda'') is a colonial seabird and the only extant member of the genus '' Alca'' of the family Alcidae, the auks. It is the closest living relative of the extinct great auk (''Pinguinis im ...

) and murrelets being the most efficient under the water, whereas the puffins and auklets are better adapted for flying and walking.

Feeding and ecology

The feeding behaviour of auks is often compared to that of penguins; both groups are

wing A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is e ...

-propelled, pursuit divers. In the region where auks live, their only seabird competition are

cormorant Phalacrocoracidae is a family of approximately 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed, but in 2021 the IOC adopted a consensus taxonomy of seven ge ...

s (which are dive-powered by their strong feet). In areas where the two groups feed on the same prey, the auks tend to feed further offshore. Strong-swimming murres hunt faster, schooling fish, whereas auklets take slower-moving krill. Time depth recorders on auks have shown that they can dive as deep as in the case of ''Uria'' guillemots, for the ''Cepphus'' guillemots and for the auklets.

Breeding and colonies

Auks are

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

birds, spending the majority of their adult lives on the open sea and going ashore only for breeding, although some species, such as the

common guillemot The common murre or common guillemot (''Uria aalge'') is a large auk. It has a circumpolar distribution, occurring in low-Arctic and boreal waters in the North Atlantic and North Pacific. It spends most of its time at sea, only coming to land to ...

, spend a great part of the year defending their nesting spot from others. Auks are monogamous, and tend to form lifelong pairs. They typically lay a single egg, and they use the nesting site year after year. Some species, such as the ''Uria'' guillemots (murres), nest in large

colonies In modern parlance, a colony is a territory subject to a form of foreign rule. Though dominated by the foreign colonizers, colonies remain separate from the administration of the original country of the colonizers, the '' metropolitan state'' ...

on cliff edges; others, such as the ''

Cepphus ''Cepphus'' is a genus of seabirds in the auk family also referred to as true guillemots or, in North America, simply as guillemots. The genus name ''Cepphus'' is from Ancient Greek ''kepphos'',. a pale waterbird mentioned by Greek authors inclu ...

'' guillemots, breed in small groups on rocky coasts; and the

s, auklets, and some murrelets nest in burrows. All species except the ''

Brachyramphus ''Brachyramphus'' is a small genus of seabirds from the North Pacific. ''Brachyramphus'' is from Ancient Greek ''brakhus'', "short", and ''rhamphos'', "bill". In English the species are named as "murrelets"; this is a diminutive of "murre", a ...

'' murrelets are colonial.

Evolution and distribution

Traditionally, the auks were believed to be one of the earliest distinct charadriiform lineages due to their characteristic morphology, but genetic analyses have demonstrated that these peculiarities are the product of strong natural selection, instead; as opposed to, for example,

plover Plovers ( , ) are a widely distributed group of wading birds belonging to the subfamily Charadriinae. Description There are about 66 species in the subfamily, most of them called "plover" or "dotterel". The closely related lapwing subf ...

s (a much older charadriiform lineage), auks radically changed from a wading

shorebird 245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...

to a diving seabird lifestyle. Thus today, the auks are no longer separated in their own suborder (Alcae), but are considered part of the

Lari Lari may refer to: Currency * Georgian lari, the currency of Georgia * Maldivian laari, or lari, a coin denomination of the rufiyaa of the Maldives Places * Lari Constituency, an electoral constituency in Kenya * Lari, Ardabil, or Lahrud, ...

suborder, which otherwise contains gulls and similar birds. Judging from genetic data, their closest living relatives appear to be the

skua The skuas are a group of predatory seabirds with seven species forming the genus ''Stercorarius'', the only genus in the family Stercorariidae. The three smaller skuas, the long-tailed skua, the Arctic skua, and the pomarine skua are calle ...

s, with these two lineages separating about 30

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago ...

(Mya). Alternatively, auks may have split off far earlier from the rest of the Lari and undergone strong morphological, but slow genetic evolution, which would require a very high

evolutionary pressure Any cause that reduces or increases reproductive success in a portion of a population potentially exerts evolutionary pressure, selective pressure or selection pressure, driving natural selection. It is a quantitative description of the amount of ...

, coupled with a long lifespan and slow reproduction. The earliest unequivocal

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s of auks are from the late

Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', ...

, some 35 Mya. The

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

'' Miocepphus'', (from the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

, 15 Mya) is the earliest known from good specimens. Two very fragmentary fossils are often assigned to the Alcidae, although this may not be correct: '' Hydrotherikornis'' (Late

) and ''

Petralca ''Petralca'' is an extinct genus of loon found in Oligocene and Miocene deposits of Austria. The type and only species, ''Petralca austriaca'', was described in 1987. It is the only member of the Petralcinae subfamily. Originally thought to be t ...

'' (Late

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but t ...

). Most extant genera are known to exist since the Late Miocene or Early

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

and

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean t ...

, but the greater diversity of fossils and tribes in the Pacific leads most scientists to conclude they first evolved there, and in the Miocene Pacific, the first fossils of extant

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

are found. Early movement between the Pacific and the Atlantic probably happened to the south (since no northern opening to the Atlantic existed), with later movements across the Arctic Ocean. The flightless subfamily

Mancallinae Mancallinae is an extinct subfamily of prehistoric flightless alcids that lived on the Pacific coast of today's California and Mexico from the late Miocene epoch to the early Pleistocene (ranging from at least 7.4 million to 470,000 years ago). ...

, which was apparently restricted to the Pacific Coast of southern North America and became extinct in the Early

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

, is sometimes includes in the family Alcidae under some definitions. One species, '' Miomancalla howardae'', is the largest charadriiform of all time. Alca torda Roest 2003

The family contains 25 extant or recently extinct species that are divided into 11 genera. The extant auks (subfamily Alcinae) are broken up into two main groups - the usually high-billed puffins (tribe Fraterculini) and auklets (tribe Aethiini), as opposed to the more slender-billed murres and true auks (tribe Alcini), and the murrelets and guillemots (tribes Brachyramphini and Cepphini). The tribal arrangement was originally based on analyses of morphology and

ecology Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overl ...

mtDNA Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA ...

cytochrome ''b''

sequence In mathematics, a sequence is an enumerated collection of objects in which repetitions are allowed and order matters. Like a set, it contains members (also called ''elements'', or ''terms''). The number of elements (possibly infinite) is called ...

s, and

allozyme Alloenzymes (or also called allozymes) are variant forms of an enzyme which differ structurally but not functionally from other allozymes coded for by different alleles at the same locus. These are opposed to isozymes, which are enzymes that pe ...

studies confirm these findings except that the ''

Synthliboramphus ''Synthliboramphus'' is a small genus of seabirds in the auk family from the North Pacific. The genus name ''Synthliboramphus'' is from Ancient Greek ''sunthlibo'', "to compress", and ''rhamphos'', "bill". The English name "Murrelet" is a dim ...

'' murrelets should be split into a distinct tribe, as they appear more closely related to the Alcini; in any case, assumption of a closer relationship between the former and the true guillemots was only weakly supported by earlier studies. Of the genera, only a few species are placed in each. This is probably a product of the rather small geographic range of the family (the most limited of any seabird family), and the periods of

glacial A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate betwe ...

advance and retreat that have kept the populations on the move in a narrow band of subarctic ocean. Today, as in the past, the auks are restricted to cooler northern waters. Their ability to spread further south is restricted as their prey hunting method, pursuit diving, becomes less efficient in warmer waters. The speed at which small fish (which along with krill are the auk's principal prey) can swim doubles as the temperature increases from , with no corresponding increase in speed for the bird. The southernmost auks, in California and Mexico, can survive there because of cold

upwelling Upwelling is an physical oceanography, oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water from deep water towards the ocean surface. It replaces the warmer and usually nutrient-depleted ...

s. The current paucity of auks in the Atlantic (six species), compared to the Pacific (19–20 species) is considered to be because of extinctions to the Atlantic auks; the fossil record shows many more species were in the Atlantic during the Pliocene. Auks also tend to be restricted to continental-shelf waters and breed on few oceanic islands. ''Hydotherikornis oregonus'' (Described by Miller in 1931), the oldest purported alcid from the Eocene of California, is actually a petrel (as reviewed by Chandler in 1990) and is reassigned to the tubenoses (Procellariiformes). A 2003 paper, "The Earliest North American Record of Auk (Aves: Alcidae) From the Late Eocene of Central Georgia", reports a Late Eocene, wing-propelled, diving auk from the Priabonain stage of the Late Eocene. These sediments have been dated through Chandronian NALMA , at an estimate of 34.5 to 35.5 million years on the Eocene time scale for fossil-bearing sediments of the Clinchfield Formation, Gordon, Wilkinson County, Georgia. Furthermore, the sediments containing this unabraded portion of a left humerus (43.7 mm long) are tropical or subtropical as evidenced by a wealth of warm-water shark teeth, palaeophied snake vertebrae, and turtles.

Systematics

* Basal and ''incertae sedis'' ** '' Miocepphus'' (

: Middle Miocene of CE USA) *** ''Miocepphus mcclungi'' Wetmore, 1940 *** ''Miocepphus bohaskai'' Wijnker and Olson, 2009 *** ''Miocepphus blowi'' Wijnker and Olson, 2009 *** ''Miocepphus mergulellus'' Wijnker and Olson, 2009 * Subfamily Alcinae ** Tribe Alcini – typical auks and murres Xantus adult

*** ''

Uria ''Uria'' is a genus of seabirds in the auk family known in Britain as guillemots, in most of North America as murres, and in Newfoundland and Labrador as turr. These are medium-sized birds with mainly brown or black plumage in the breeding ...

'' ****

Common murre The common murre or common guillemot (''Uria aalge'') is a large auk. It has a circumpolar distribution, occurring in low-Arctic and boreal waters in the North Atlantic and North Pacific. It spends most of its time at sea, only coming to land t ...

or common guillemot, ''Uria aalge'' ****

Thick-billed murre The thick-billed murre or Brünnich's guillemot (''Uria lomvia'') is a bird in the auk family (Alcidae). This bird is named after the Danish zoologist Morten Thrane Brünnich. The very deeply black North Pacific subspecies ''Uria lomvia arra ...

or, Brünnich's guillemot, ''Uria lomvia'' *** ''

Alle Alle may refer to: *The German name for the Łyna River, a river since 1945 in Poland and the Russian Kaliningrad Oblast *Alle, Switzerland, a community in the Swiss canton of Jura *Alle, Belgium in the province of Namur, Belgium * Little auk (''A ...

'' ****

Little auk The little auk or dovekie (''Alle alle'') is a small auk, the only member of the genus ''Alle''. ''Alle'' is the Sami name of the long-tailed duck; it is onomatopoeic and imitates the call of the drake duck. Linnaeus was not particularly f ...

or dovekie, ''Alle alle'' *** '' Pinguinus'' ****

Great auk The great auk (''Pinguinus impennis'') is a species of flightless alcid that became extinct in the mid-19th century. It was the only modern species in the genus ''Pinguinus''. It is not closely related to the birds now known as penguins, wh ...

, ''Pinguinus impennis'' (

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

, c.1844) *** '' Alca'' ****

Razorbill The razorbill, razor-billed auk, or lesser auk (''Alca torda'') is a colonial seabird and the only extant member of the genus '' Alca'' of the family Alcidae, the auks. It is the closest living relative of the extinct great auk (''Pinguinis im ...

, ''Alca torda'' ** Tribe Synthliboramphini – synthliboramphine murrelets Blackguillemot44

*** ''

'' ****

Scripps's murrelet Scripps's murrelet (''Synthliboramphus scrippsi'') is a small seabird found in the California Current system in the Pacific Ocean. This auk breeds on islands off California and Mexico. It is threatened by predators introduced to its breeding ...

, ''Synthliboramphus scrippsi'' – formerly in ''S. hypoleucus'' (" Xantus's murrelet") ****

Guadalupe murrelet The Guadalupe murrelet (''Synthliboramphus hypoleucus'') or Xantus' Murrelet is a small seabird found in the California Current system in the Pacific Ocean. This auk breeds on islands off California and Mexico. It is threatened by predators intr ...

, ''Synthliboramphus hypoleucus'' – sometimes separated in ''Endomychura'' ****

Craveri's murrelet Craveri's murrelet (''Synthliboramphus craveri'') is a small seabird which breeds on offshore islands in both the Pacific Ocean and the Gulf of California off the Baja peninsula of Mexico. It also wanders fairly regularly as far as central Cali ...

, ''Synthliboramphus craveri'' – sometimes separated in ''Endomychura'' ****

Ancient murrelet The ancient murrelet (') is a bird in the auk family. The English term "murrelet" is a diminutive of "murre", a word of uncertain origins, but which may imitate the call of the common guillemot. Ancient murrelets are called "ancient" because th ...

, ''Synthliboramphus antiquus'' **** Japanese murrelet, ''Synthliboramphus wumizusume'' ** Tribe Cepphini – true guillemots Marbled murrelet breeding plumage

*** ''

'' ****

Black guillemot The black guillemot or tystie (''Cepphus grylle'') is a medium-sized seabird of the Alcidae family, native throughout northern Atlantic coasts and eastern North American coasts. It is resident in much of its range, but large populations from the ...

or tystie, ''Cepphus grylle'' ****

Pigeon guillemot The pigeon guillemot (''Cepphus columba'') () is a species of bird in the auk family, Alcidae. One of three species in the genus '' Cepphus'', it is most closely related to the spectacled guillemot. There are five subspecies of the pigeon gu ...

, ''Cepphus columba'' ***** Kurile guillemot, ''Cepphus columba snowi'' ****

Spectacled guillemot The spectacled guillemot or sooty guillemot (''Cepphus carbo'') is a seabird in the auk family. Description This species is about with red legs, black bill, and a blackish iris. The breeding adult spectacled guillemot is distinctive, mostly p ...

, ''Cepphus carbo'' ** Tribe Brachyramphini – brachyramphine murrelets *** ''

'' **** Marbled murrelet, ''Brachyramphus marmoratus'' ****

Long-billed murrelet The long-billed murrelet (''Brachyramphus perdix'') is a small seabird from the North Pacific. The genus name ''Brachyramphus'' is from Ancient Greek ''brakhus'', "short", and ''rhamphos'', "bill". The species name ''perdix'' is Latin for "par ...

, ''Brachyramphus perdix'' ****

Kittlitz's murrelet Kittlitz's murrelet (''Brachyramphus brevirostris'') is a small alcid found in the waters off Alaska and Eastern Siberia. This near threatened species is, like the closely related marbled murrelet, unusual for seabirds in not being colonial, n ...

, ''Brachyramphus brevirostris'' * Subfamily Fraterculinae ** Tribe Aethiini – auklets Puffin Mrkoww

*** '' Ptychoramphus'' ****

Cassin's auklet Cassin's auklet (''Ptychoramphus aleuticus'') is a small, chunky seabird that ranges widely in the North Pacific. It is the only species placed in the genus ''Ptychoramphus''. It nests in small burrows and because of its presence on well studied ...

, ''Ptychoramphus aleuticus'' *** ''

Aethia ''Aethia'' is a genus of four small (85–300g) auklets endemic to the North Pacific Ocean, Bering Sea and Sea of Okhotsk and among some of North America's most abundant seabirds. The relationships between the four true auklets remains unclear. ...

'' ****

Parakeet auklet The parakeet auklet (''Aethia psittacula'') is a small seabird of the North Pacific. Parakeet Auklets used to be placed on its own in the genus ''Cyclorrhynchus'' ( Kaup, 1829) but recent morphological and genetic evidence suggest it should be p ...

, ''Aethia psittacula'' **** Crested auklet, ''Aethia cristatella'' ****

Whiskered auklet The whiskered auklet (''Aethia pygmaea'') is a small seabird of the auk family. It has a more restricted range than other members of its genus, ''Aethia'', living only around the Aleutian Islands and on some islands off Siberia (like Commander ...

, ''Aethia pygmaea'' **** Least auklet, ''Aethia pusilla'' ** Tribe Fraterculini – puffins *** '' Cerorhinca'' ****

Rhinoceros auklet The rhinoceros auklet (''Cerorhinca monocerata'') is a seabird and a close relative of the puffins. It is the only extant species of the genus ''Cerorhinca''. Given its close relationship with the puffins, the common name rhinoceros puffin has b ...

, ''Cerorhinca monocerata'' *** '' Fratercula'' ****

Atlantic puffin The Atlantic puffin ('), also known as the common puffin, is a species of seabird in the auk family. It is the only puffin native to the Atlantic Ocean; two related species, the tufted puffin and the horned puffin is found in the northeastern ...

, ''Fratercula arctica'' ****

Horned puffin The horned puffin (''Fratercula corniculata'') is an auk found in the North Pacific Ocean, including the coasts of Alaska, Siberia and British Columbia. It is a pelagic seabird that feeds primarily by diving for fish. It nests in colonies, often ...

, ''Fratercula corniculata'' ****

Tufted puffin The tufted puffin (''Fratercula cirrhata''), also known as crested puffin, is a relatively abundant medium-sized pelagic seabird in the auk family (Alcidae) found throughout the North Pacific Ocean. It is one of three species of puffin that make ...

, ''Fratercula cirrhata''

Biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic ('' genetic variability''), species ('' species diversity''), and ecosystem ('' ecosystem diversity'') ...

of auks seems to have been markedly higher during the Pliocene. See the genus accounts for prehistoric species.

References

External links

* {{Authority control Diving animals Extant Eocene first appearances Priabonian first appearances Taxa named by William Elford Leach

Description

Feeding and ecology

Breeding and colonies

Evolution and distribution

Systematics

See also

References

Further reading

External links