Editing Great auk (section)

==Ecology and behaviour==
[[File:PinguinusImpennus.jpg|alt=Two summer great auks, one swimming and facing right while another stands upon a rock looking left, are surrounded by steep, rocky cliffs.|thumb|Great Auks by [[John James Audubon]], from ''[[The Birds of America]]'' (1827–1838)]]
The great auk was never observed and described by modern scientists during its existence and is only known from the accounts of laymen, such as sailors, so its behaviour is not well known and difficult to reconstruct. Much may be inferred from its close, living relative, the [[razorbill]], as well as from remaining soft tissue.<ref name=Fuller2003/>

Great auks walked slowly and sometimes used their wings to help them traverse rough terrain.<ref name="FOM 1864">{{cite book| author = [[Francis Orpen Morris|Morris, Reverend Francis O]].|title =A History of British Birds| year = 1864 |volume = 6| publisher = Groombridge and Sons, Paternoster Way, London|pages= 56–58 |url =https://books.google.com/books?id=GEkDAAAAQAAJ&pg=PA58}}</ref> When they did run, it was awkwardly and with short steps in a straight line.<ref name="BNABehavior" /> They had few natural predators, mainly large [[marine mammal]]s, such as the [[orca]], and [[white-tailed eagle]]s.<ref name="BNABehavior">{{Cite web | last = Montevecchi | first = William A. |author2=David A. Kirk | title =Behavior-Great Auk (''Pinguinus impennis'') | work = The Birds of North America Online | publisher = Cornell Lab of Ornithology | year = 1996 | url = http://bna.birds.cornell.edu/bna/species/260/articles/behavior| access-date =28 April 2010 }} {{subscription required}}</ref> Polar bears preyed on nesting colonies of the great auk.<ref name=Crofford_1989/>{{rp|page=35}} Based on observations by the Naturalist Otto Fabricius (the only scientist to make primary observations on the great auk), some auks were "stupid and tame" whilst others were difficult to approach which he suggested was related to the bird's age.<ref name="Meldegaard" /> Humans preyed upon them as food, for feathers, and as specimens for museums and [[egg collecting|private collections]].<ref name="iucn status 19 November 2021" /> Great auks reacted to noises, but were rarely frightened by the sight of something.<ref name=Cokinos2000/>{{rp|page=315}} They used their bills aggressively both in the dense nesting sites and when threatened or captured by humans.<ref name="BNABehavior" /> These birds are believed to have had a life span of approximately 20 to 25 years.<ref name=Cokinos2000/>{{rp|page=313}} During the winter, the great auk migrated south, either in pairs or in small groups, but never with the entire nesting colony.<ref name=Crofford_1989/>{{rp|page=32}}

The great auk was generally an excellent swimmer, using its wings to propel itself underwater.<ref name="FOM 1864" /> While swimming, the head was held up but the neck was drawn in.<ref name="BNABehavior" /> This species was capable of banking, veering, and turning underwater.<ref name=Crofford_1989/>{{rp|page=32}} The great auk was known to dive to depths of {{convert|75|m|ft|-1|abbr=on}} and it has been claimed that the species was able to dive to depths of {{convert|1|km|ft fathom|abbr=on}}.<ref name=Cokinos2000/>{{rp|page=311}} To conserve energy, most dives were shallow.<ref name="BNAFood" /> It also could hold its breath for 15 minutes, longer than a seal. Its ability to dive so deeply reduced competition with other alcid species. The great auk was capable of accelerating underwater, then shooting out of the water to land on a rocky ledge above the ocean's surface.<ref name=Crofford_1989/>{{rp|page=32}}

===Diet===
[[File:Alca Impennis by John Gould.jpg|alt=A summer great auk tilts its head back, swallowing a fish.|thumb|Great auk eating a fish, by [[John Gould]]]]
This alcid typically fed in shoaling waters that were shallower than those frequented by other alcids,<ref name="BNAFood">{{Cite web | last = Montevecchi | first = William A. |author2=David A. Kirk | title =Food Habits-Great Auk (''Pinguinus impennis'') | work = The Birds of North America Online | publisher = Cornell Lab of Ornithology | year = 1996 | url = http://bna.birds.cornell.edu/bna/species/260/articles/foodhabits| access-date =29 April 2010 }} {{subscription required}}</ref> although after the breeding season, they had been sighted as far as {{convert|500|km|nmi|abbr=on}} from land.<ref name="BNAFood" /> They are believed to have fed cooperatively in flocks.<ref name="BNAFood" /> Their main food was fish, usually {{convert|12|to|20|cm|in|frac=2|abbr=on}} in length and weighing {{convert|40|to|50|g|oz|frac=8|abbr=on}}, but occasionally their prey was up to half the bird's own length. Based on remains associated with great auk bones found on [[Funk Island]] and on ecological and morphological considerations, it seems that [[Atlantic menhaden]] and [[capelin]] were their favoured prey.<ref>{{cite journal |last =Olson |first = Storrs L|author2 = Swift, Camm C. |author3 = Mokhiber, Carmine |year =1979 |title = An attempt to determine the prey of the Great Auk (''Pinguinus impennis'') |journal = [[The Auk]] |volume = 96 |issue =4 |jstor =4085666 |pages = 790–792}}</ref> Other fish suggested as potential prey include [[lumpsucker]]s, [[shorthorn sculpin]]s, [[cod]], [[sand lance]], as well as crustaceans.<ref name=Cokinos2000/>{{rp|page=311}}<ref name="BNAFood" /> The young of the great auk are believed to have eaten [[plankton]] and, possibly, fish and crustaceans regurgitated by adults.<ref name="BNA" /><ref name=Cokinos2000/>{{rp|page=313}}

===Reproduction===
[[File:Pinguinus.jpg|thumb|upright|left|Nesting ground with juveniles and eggs, by Keulemans]]
Historical descriptions of the great auk breeding behaviour are somewhat unreliable.<ref>{{Cite journal | doi = 10.1111/j.1474-919x.2003.00227.x| title = Remarks on the terminology used to describe developmental behaviour among the auks (Alcidae), with particular reference to that of the Great Auk ''Pinguinus impennis''| journal = Ibis| volume = 146| issue = 2| pages = 231–240| year = 2003| last1 = Gaskell | first1 = J. }}</ref> Great Auks began pairing in early and mid-May.<ref name="BNABreeding">{{Cite web | last = Montevecchi | first = William A. |author2=David A. Kirk | title =Breeding-Great Auk (''Pinguinus impennis'') | work = The Birds of North America Online | publisher = Cornell Lab of Ornithology | year = 1996 | url = http://bna.birds.cornell.edu/bna/species/260/articles/breeding| access-date =29 April 2010 }} {{subscription required}}</ref> They are believed to have mated for life (although some theorize that great auks could have mated outside their pair, a trait seen in the razorbill).<ref name="BNABehavior" /><ref name=Cokinos2000/>{{rp|page=313}} Once paired, they nested at the base of cliffs in colonies, likely where they copulated.<ref name=Crofford_1989/>{{rp|page=28}}<ref name="BNABehavior" /> Mated pairs had a social display in which they bobbed their heads and displayed their white eye patch, bill markings, and yellow mouth.<ref name="BNABehavior" /> These colonies were extremely crowded and dense, with some estimates stating that there was a nesting great auk for every {{convert|1|m2|sqft}} of land.<ref name="BNABehavior" /> These colonies were very social.<ref name="BNABehavior" /> When the colonies included other species of alcid, the great auks were dominant due to their size.<ref name="BNABehavior" />

[[File:Pinguinus impennis eggs Zoothèque MNHN.jpg|thumb|Eggs in [[Muséum national d'histoire naturelle]]]]
Female great auks would lay only one egg each year, between late May and early June, although they could lay a replacement egg if the first one was lost.<ref name=Crofford_1989/>{{rp|page=32}}<ref name="BNABreeding" /> In years when there was a shortage of food, the great auks did not breed.<ref name="BNADemography" /> A single egg was laid on bare ground up to {{convert|100|m|ft}} from shore.<ref name="FOM 1864" /><ref name=Crofford_1989/>{{rp|page=33}} The egg was ovate and elongate in shape, and it averaged {{convert|12.4|cm|in|frac=8|abbr=on}} in length and {{convert|7.6|cm|in|frac=8|abbr=on}} across at the widest point.<ref name="Gaskell">{{cite book|url =https://books.google.com/books?id=tsUzeXV_7jcC&q=egg+%22Great+Auk%22&pg=PA152 |title = Who Killed the Great Auk?| first = Jeremy |last =Gaskell |publisher = Oxford University Press (US)|isbn = 0-19-856478-3 |year = 2000|page= 152}}</ref><ref name=Crofford_1989/>{{rp|page=35}} The egg was yellowish white to light ochre with a varying pattern of black, brown, or greyish spots and lines that often were congregated on the large end.<ref name="FOM 1864" /><ref name="Egg">{{cite web|url=http://www.museums.norfolk.gov.uk/default.asp?Document=300.40.20&Image=577&gst= |title=Great Auk egg |publisher=Norfolk Museums & Archaeology Service |access-date=8 May 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090209223346/http://www.museums.norfolk.gov.uk/default.asp?Document=300.40.20&Image=577&gst= |archive-date=9 February 2009 }}</ref> It is believed that the variation in the egg streaks enabled the parents to recognize their egg among those in the vast colony.<ref name="BNABreeding" /> The pair took turns incubating the egg in an upright position for the 39 to 44 days before the egg hatched, typically in June, although eggs could be present at the colonies as late as August.<ref name=Crofford_1989/>{{rp|page=35}}<ref name="BNABreeding" />

The parents also took turns feeding their chick. According to one account, the chick was covered with grey down.<ref name=Cokinos2000/>{{rp|page=313}} The young bird took only two or three weeks to mature enough to abandon the nest and land for the water, typically around the middle of July.<ref name=Crofford_1989/>{{rp|page=35}}<ref name="BNABreeding" /> The parents cared for their young after they fledged, and adults would be seen swimming with their young perched on their backs.<ref name="BNABreeding" /> Great auks matured sexually when they were four to seven years old.<ref name="BNADemography">{{Cite web | last = Montevecchi | first = William A. |author2=David A. Kirk | title =Demography-Great Auk (''Pinguinus impennis'') | work = The Birds of North America Online | publisher = Cornell Lab of Ornithology | year = 1996 | url = http://bna.birds.cornell.edu/bna/species/260/articles/demography| access-date =29 April 2010 }}</ref>