Editing Auk (section)

==Evolution and distribution==
{{See also|List of Charadriiformes by population}}
[[File:Auks.jpg|thumb|upright|Auks as painted by [[Archibald Thorburn]]]] 
Traditionally, the auks were believed to be one of the earliest distinct charadriiform lineages due to their characteristic [[morphology (biology)|morphology]], but genetic analyses have demonstrated that these peculiarities are the product of strong natural selection, instead; as opposed to, for example, [[plover]]s (a much older charadriiform lineage), auks radically changed from a wading [[wader|shorebird]] 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 (bird)|Lari]] suborder, which otherwise contains gulls and similar birds. Judging from genetic data, their closest living relatives appear to be the [[skua]]s, with these two lineages separating about 30 [[year|million years ago]] (Mya).<ref name=Friesen/><ref name=Moum/><ref name=Thomas/> 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]], coupled with a long lifespan and slow reproduction.

The earliest unequivocal [[fossil]]s of auks are from the late [[Eocene]], some 35 Mya.<ref name=smith2011/> The [[genus]] ''Miocepphus'' (from the [[Miocene]], 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]]) and ''[[Petralca]]'' (Late [[Oligocene]]). Most extant genera are known to exist since the Late Miocene or Early [[Pliocene]] (about 5 Mya). Miocene fossils have been found in both [[California]] and [[Maryland]], 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 [[genus|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]].<ref name = konyukhov2002/> The flightless subfamily [[Mancallinae]], which was apparently restricted to the Pacific Coast of southern North America and became extinct in the Early [[Pleistocene]], is sometimes included in the family Alcidae under some definitions. One species, ''[[Miomancalla howardae]]'', is the largest charadriiform of all time.<ref>{{cite journal |last1=Smith |first1=N. A. |title=Evolution of body mass in the Pan-Alcidae (Aves, Charadriiformes): the effects of combining neontological and paleontological data |journal=[[Paleobiology (journal)|Paleobiology]] |date=2015 |volume=42 |issue=1 |pages=8–26 |doi=10.1017/pab.2015.24|s2cid=83934750 }}</ref>

[[File:Alca torda Roest 2003.jpg|thumb|left|[[Razorbill]]s are auks found in the [[Atlantic Ocean]].]]
The family contains 25 extant or recently extinct species that are divided into 11 genera.<ref name=ioc>{{cite web| editor1-last=Gill | editor1-first=Frank | editor1-link=Frank Gill (ornithologist) | editor2-last=Donsker | editor2-first=David | editor3-last=Rasmussen | editor3-first=Pamela | editor3-link=Pamela Rasmussen | date=August 2022 | title=Noddies, gulls, terns, skimmers, skuas, auks | work=IOC World Bird List Version 12.2 | url=https://www.worldbirdnames.org/bow/gulls/ | publisher=International Ornithologists' Union | access-date=10 November 2022 }}</ref> 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]].<ref name = strauch1985/> [[mitochondrial DNA|mtDNA]] [[cytochrome b|cytochrome ''b'']] [[Nucleic acid sequence|sequence]]s, and [[allozyme]] studies<ref name=Friesen/><ref name=Moum/> 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.<ref name = strauch1985 />

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 [[glacier|glacial]] 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 {{convert|5|to|15|C}}, with no corresponding increase in speed for the bird. The southernmost auks, in California and Mexico, can survive there because of cold [[upwelling]]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", <!-- by Robert M. Chandler and Dennis Parmley of Georgia College and State University --> reports a Late Eocene, wing-propelled, diving auk from the Priabonain stage of the Late Eocene. These sediments have been dated through Chandronian NALMA {North American Land Mammal Age}, 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.