Editing Penguin (section)

==Behaviour==
[[File:Pygoscelis antarctica trying to get to iceberg.wmv.OGG|thumb|[[Chinstrap penguin]]s in [[Antarctica]]]]

===Breeding===
{{Css Image Crop|Image = Brown Bluff-2016-Tabarin Peninsula–Gentoo penguin (Pygoscelis papua) 05.jpg|bSize = 450|cWidth = 220|cHeight = 250|oTop = 50|oLeft = 110|Location = right|Description = [[Gentoo penguin]] watching over a sleeping chick at [[Brown Bluff]]}}
Penguins for the most part breed in large colonies, the exceptions being the yellow-eyed and Fiordland species; these colonies may range in size from as few as 100 pairs for gentoo penguins to several hundred thousand in the case of king, macaroni and chinstrap penguins.<ref name=Will17>[[#Williams|Williams]], p. 17</ref> Living in colonies results in a high level of social interaction between birds, which has led to a large repertoire of visual as well as vocal displays in all penguin species.<ref name=Williams57>[[#Williams|Williams]], p. 57</ref> ''Agonistic'' displays are those intended to confront or drive off, or alternately appease and avoid conflict with, other individuals.<ref name=Williams57/>

Penguins form monogamous pairs for a breeding season, though the rate the same pair recouples varies drastically. Most penguins lay two eggs in a clutch, although the two largest species, the emperor and the [[king penguin]]s, lay only one.<ref name=Will23>[[#Williams|Williams]], p. 23</ref> With the exception of the emperor penguin, where the male does it all, all penguins share the [[Avian incubation|incubation]] duties.<ref>{{Cite journal | doi = 10.1080/03014223.2000.9518236| title = Prolonged foraging trips and egg desertion in little penguins (''Eudyptula minor'')| journal = New Zealand Journal of Zoology| volume = 27| issue = #4| pages = 277–289| year = 2000| last1 = Numata | first1 = M. | last2 = Davis | first2 = L. S. | last3 = Renner | first3 = M. | doi-access = free}}</ref> These incubation shifts can last days and even weeks as one member of the pair feeds at sea.

Penguins generally only lay one brood; the exception is the little penguin, which can raise two or three broods in a season.<ref>{{cite book|vauthors=Reilly PN, Balmford P |title=The Biology of Penguins|editor=Stonehouse, Bernard|publisher=Macmillan|location=London|year=1975|pages=161–87|chapter=A breeding study of the little penguin, ''Eudyptula minor'', in Australia |isbn=978-0-333-16791-5}}</ref>

Penguin eggs are smaller than any other bird species when compared proportionally to the weight of the parent birds; at {{convert|52|g|oz|0|abbr=on}}, the little penguin egg is 4.7% of its mothers' weight, and the {{convert|450|g|lb|0|abbr=on}} emperor penguin egg is 2.3%.<ref name=Will23/> The relatively thick shell forms between 10 and 16% of the weight of a penguin egg, presumably to reduce the effects of dehydration and to minimize the risk of breakage in an adverse nesting environment.<ref>{{cite book|author=Meyer-Rochow V.B.|title=Advances in Animal Science and Zoology| editor=Jenkins Owen P.|publisher=Nova Sci Publ Inc|location=Hauppauge, N.Y.|year=2015|pages=65–80|chapter=Examples of four incompletely resolved aspects of the biology of penguins elated to digestive and reproductive physiology, vision and locomotion | isbn =978-1-63483-328-8}}</ref> The yolk, too, is large and comprises 22–31% of the egg. Some yolk often remains when a chick is born, and is thought to help sustain the chick if the parents are delayed in returning with food.<ref name=Will24>[[#Williams|Williams]], p. 24</ref>

When emperor penguin mothers lose a chick, they sometimes attempt to "steal" another mother's chick, usually unsuccessfully as other females in the vicinity assist the defending mother in keeping her chick.<ref>{{cite news |last1=Gorvett |first1=Zaria |title=If you think penguins are cute and cuddly, you're wrong |url=http://www.bbc.com/earth/story/20151223-if-you-think-penguins-are-cute-and-cuddly-youre-wrong |access-date=March 9, 2020 |work=BBC Earth |date=December 23, 2015 |archive-date=March 8, 2020 |archive-url=https://web.archive.org/web/20200308055345/http://www.bbc.com/earth/story/20151223-if-you-think-penguins-are-cute-and-cuddly-youre-wrong |url-status=live }}</ref> In some species, such as emperor and king penguins, the chicks assemble in large groups called [[Crèche (zoology)|crèches]].