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
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, auklets, and some murrelets nest in burrows. All species except the ''
Brachyramphus'' murrelets are colonial.
Evolution and distribution
![Auks](https://upload.wikimedia.org/wikipedia/commons/c/c0/Auks.jpg)
Traditionally, the auks were believed to be one of the earliest distinct charadriiform lineages due to their characteristic
morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
* Morphology (archaeology), study of the shapes or forms of artifacts
* Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...
, 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 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 called ...
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 epoch (geology), 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 mea ...
, 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 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'', " ...
) and '' Petralca'' (Late Oligocene). 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 2.58[California
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 ...](_blank)
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 to ...
, 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 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 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 finally confirmed in ...
, is sometimes includes in the family Alcidae under some definitions. One species, '' Miomancalla howardae'', is the largest charadriiform of all time.
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 calle ...
s, and allozyme studies[ confirm these findings except that the '' Synthliboramphus'' 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 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 surface water. The nut ...
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'' (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 ...
: 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
*** ''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 s ...
''
**** 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 to ...
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''
**** 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 fam ...
or dovekie, ''Alle alle''
*** '' Pinguinus''
**** Great auk, ''Pinguinus impennis'' ( extinct, 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
*** '' Synthliboramphus''
**** Scripps's murrelet, ''Synthliboramphus scrippsi'' – formerly in ''S. hypoleucus'' (" Xantus's murrelet")
**** Guadalupe murrelet, ''Synthliboramphus hypoleucus'' – sometimes separated in ''Endomychura''
**** Craveri's murrelet, ''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
The Japanese murrelet or crested murrelet (''Synthliboramphus wumizusume'') is a small seabird in the auk family that occurs along the remote rocky coasts and in the offshore waters of Japan, and may also be found after the breeding season as far ...
, ''Synthliboramphus wumizusume''
** Tribe Cepphini – true guillemots
*** ''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 ...
''
**** Black guillemot 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 guil ...
, ''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
*** '' Brachyramphus''
**** Marbled murrelet, ''Brachyramphus marmoratus''
**** Long-billed murrelet, ''Brachyramphus perdix''
**** Kittlitz's murrelet, ''Brachyramphus brevirostris''
* Subfamily Fraterculinae
** Tribe Aethiini – auklets
*** '' 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. A ...
''
**** Parakeet auklet, ''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
The least auklet (''Aethia pusilla'') is a seabird and the smallest species of auk. It is the most abundant seabird in North America, and one of the most abundant in the world, with a population of around nine million birds. They breed on the isl ...
, ''Aethia pusilla''
** Tribe Fraterculini – puffins
*** '' Cerorhinca''
**** Rhinoceros auklet, ''Cerorhinca monocerata''
*** '' Fratercula''
**** Atlantic puffin, ''Fratercula arctica''
**** Horned puffin, ''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'') l ...
of auks seems to have been markedly higher during the Pliocene. See the genus accounts for prehistoric species.
See also
* ''Kiviak
Kiviak or kiviaq is a traditional wintertime Inuit food from Greenland that is made of little auks (''Alle alle''), a type of seabird, fermented in a seal skin.
Up to 500 whole auks are packed into the seal skin, beaks and feathers included. A ...
'', a traditional Inuit food from Greenland that is made of auks preserved in seal skin
* Tradeoffs for locomotion in air and water
References
Further reading
*
*
*
''Diving Birds of North America''
by Paul Johnsgard
Paul Austin Johnsgard (28 June 1931 – 28 May 2021) was an ornithologist, artist and emeritus professor at the University of Nebraska. His works include nearly fifty books including several monographs, principally about the waterfowl and cranes.
...
External links
*
{{Authority control
Diving animals
Extant Eocene first appearances
Priabonian first appearances
Taxa named by William Elford Leach