View source for Mergus

{{Short description|Genus of birds}}
{{Redirect|Merganser|the white merganser|Smew|other meanings|Merganser (disambiguation)}}
{{Automatic taxobox
| name = Typical mergansers
| image = Mergus serrator.jpg
| image_caption = [[Red-breasted merganser]] (''Mergus serrator'')
| taxon = Mergus
| authority = [[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]]
| type_species = ''[[Mergus serrator]]''
| type_species_authority = [[Carl Linnaeus|Linnaeus]], 1758
| subdivision_ranks = Species
| subdivision = {{dagger}}''[[New Zealand merganser|Mergus australis]]'' <small>Auckland Island merganser</small><br/>
''[[Common merganser|Mergus merganser]]'' <small>Common merganser</small><br/>
{{dagger}}''[[Mergus milleneri]]'' <small>Chatham merganser</small><br/>
''[[Brazilian merganser|Mergus octosetaceus]]'' <small>Brazilian merganser</small><br/>
''[[Red-breasted merganser|Mergus serrator]]'' <small>Red-breasted merganser</small><br/>
''[[Scaly-sided merganser|Mergus squamatus]]'' <small>Scaly-sided merganser</small>
}}

'''''Mergus''''' is the [[genus]] of the '''typical mergansers''' ({{IPAc-en|m|ɜːr|ˈ|ɡ|æ|n|s|ər|z}} {{respell|mur|GAN|sərz}}),<ref>{{Cite book|title=The Chambers Dictionary|publisher=Chambers|year=2003|isbn=0-550-10105-5|edition=9th|chapter=merganser}}</ref> fish-eating [[duck]]s in the subfamily [[Anatinae]]. The genus name is a Latin word used by [[Pliny the Elder]] and other [[Ancient Rome|Roman]] authors to refer to an unspecified waterbird.<ref name= job90>{{cite book | last= Jobling | first= James A | year= 2010| title= The Helm Dictionary of Scientific Bird Names | url= https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling | publisher = Christopher Helm | location = London | isbn = 978-1-4081-2501-4 |page =[https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling/page/251 251]}}</ref><ref name=Arnott/>

The [[common merganser]] (''Mergus merganser'') and [[red-breasted merganser]] (''M.&nbsp;serrator'') have broad ranges in the northern hemisphere. The [[Brazilian merganser]] (''M.&nbsp;octosetaceus'') is a South American duck, and one of the six most [[Threatened species|threatened]] [[waterfowl]] in the world, with possibly fewer than 250 birds in the wild. The [[scaly-sided merganser]] or "Chinese merganser" (''M.&nbsp;squamatus'') is an [[endangered]] species. It lives in [[temperate]] East Asia, breeding in the north and wintering in the south.

The [[hooded merganser]] (''Lophodytes cucullatus'', formerly known as ''Mergus cucullatus'') is not of this genus but is closely related. The other "aberrant" merganser, the [[smew]] (''Mergellus albellus''), is [[phylogenetics|phylogenetically]] closer to [[goldeneye (duck)|goldeneye]]s (''Bucephala'').

Although they are [[Mergini|seaducks]], most of the mergansers prefer riverine habitats, with only the red-breasted merganser being common at sea. These large [[piscivore|fish-eaters]] typically have black-and-white, brown or green hues in their plumage, and most have somewhat shaggy crests. All have serrated edges to their long and thin bills that help them grip their prey. Along with the smew and hooded merganser, they are therefore often known as "sawbills". The goldeneyes, on the other hand, feed mainly on [[mollusk]]s, and therefore have a more typical duck-bill.<ref>{{cite web|title=Common Goldeneye|url=http://www.birdweb.org/birdweb/bird/common_goldeneye|publisher=Seattle Audubon Society|access-date=18 April 2014}}</ref>

''Mergus'' ducks are also classified as "diving ducks" because they submerge completely in looking for food. In other traits, however, the genera ''Mergus'', ''Lophodytes'', ''Mergellus'', and ''Bucephala'' are very similar: uniquely among all [[Anseriformes]], they do not have notches at the hind margin of their [[sternum]], but holes surrounded by bone.<ref name=Livezey/>

==Taxonomy==
The [[genus]] ''Mergus'' was introduced in 1758 by the Swedish naturalist [[Carl Linnaeus]] in the [[10th edition of Systema Naturae|tenth edition]] of his ''[[Systema Naturae]]''.<ref>{{cite book | last=Linnaeus | first=Carl | author-link=Carl Linnaeus | year=1758 | title= Systema Naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis | volume=1 | edition=10th | page=129 | publisher=Laurentii Salvii | location=Holmiae (Stockholm) | language=Latin | url=https://www.biodiversitylibrary.org/page/727034 }}</ref> The genus name is the [[Latin]] word for an unidentified waterbird mentioned by [[Pliny the Elder]] and other authors; some sources have identified the original ''mergus'' as referring to either a [[cormorant]] or [[Scopoli's shearwater]].<ref>{{cite book | last=Jobling | first=James A. | year=2010| title= The Helm Dictionary of Scientific Bird Names | publisher=Christopher Helm | location=London | isbn= 978-1-4081-2501-4 | page=251 | url=https://archive.org/stream/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling#page/n251/mode/1up }}</ref><ref>{{Cite journal |last=Arnott |first=W. G. |date=1964 |title=Notes on Gavia and Mergvs in Latin Authors [Notes on Gavia and Mergus in Latin Authors] |url=https://www.jstor.org/stable/637729 |journal=The Classical Quarterly |volume=14 |issue=2 |pages=249–262 |doi=10.1017/S0009838800023806 |jstor=637729 |s2cid=170648873 |issn=0009-8388|url-access=subscription }}</ref><ref>{{Cite journal |last=White |first=Heather |date=2011 |title=Language and style in Ovid |url=https://ojs.ehu.eus/index.php/Veleia/article/view/6309 |journal=Veleia |language=es |issue=28 |doi=10.1387/veleia.6309 |doi-broken-date=12 July 2025 |issn=2444-3565}}</ref><ref>{{Cite web |title=Ornithological Approaches to Greek Mythology: The Case of the Shearwater |url=https://camws.org/sites/default/files/meeting2018/abstracts/029.OrnithologicalApproachestoGreekMythology.pdf |website=CAMWS}}</ref> The [[type species]] was designated as ''Mergus serrator'' [[Carl Linnaeus|Linnaeus]], 1758 (the [[red-breasted merganser]]) by [[Thomas Campbell Eyton]] in 1838.<ref>{{ cite book | last=Eyton | first=Thomas Campbell | author-link=Thomas Campbell Eyton | date=1838 | title=A Monograph on the Anatidae, or Duck Tribe | location=London | publisher=Longman, Orme, Brown, Green, & Longman | page=76 | url=https://www.biodiversitylibrary.org/page/36002202 }}</ref><ref>{{ cite book | editor1-last=Mayr | editor1-first=Ernst | editor1-link=Ernst Mayr | editor2-last=Cottrell | editor2-first=G. William | year=1979 | title=Check-List of Birds of the World | volume=1 | edition=2nd | publisher=Museum of Comparative Zoology | place=Cambridge, Massachusetts | page=496 | url=https://www.biodiversitylibrary.org/page/16109136 }}</ref><ref>{{ cite book | editor1-last=Dickinson | editor1-first=E.C. | editor1-link=Edward C. Dickinson | editor2-last=Remsen | editor2-first=J.V. Jr. | editor2-link=James Van Remsen Jr. | year=2013 | title=The Howard & Moore Complete Checklist of the Birds of the World | volume=1: Non-passerines | edition=4th | location=Eastbourne, UK | publisher=Aves Press | isbn=978-0-9568611-0-8 | page=12 | url=https://archive.org/details/howardmoorecompl0001howa/page/12/mode/1up | url-access=registration }}</ref>

===Recent species===
The genus contains four living species and two [[Holocene extinction|recently extinct]] species.<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=July 2021 | title=Screamers, ducks, geese & swans | work=IOC World Bird List Version 11.2 | url=http://www.worldbirdnames.org/bow/waterfowl/ | publisher=International Ornithologists' Union | accessdate=24 August 2021 }}</ref><ref>{{Cite web |title=Auckland Island merganser {{!}} Miuweka {{!}} New Zealand Birds Online |url=https://www.nzbirdsonline.org.nz/species/auckland-island-merganser |access-date=2022-05-30 |website=www.nzbirdsonline.org.nz}}</ref><ref name=":0">{{Cite web |title=Chatham Island merganser {{!}} New Zealand Birds Online |url=https://nzbirdsonline.org.nz/species/chatham-island-merganser |access-date=2022-05-30 |website=nzbirdsonline.org.nz |language=en}}</ref>

{{Species table |genus= Mergus |authority-name=[[Carl Linnaeus|Linnaeus]] |authority-year=[[10th edition of Systema Naturae|1758]] |species-count=two|no-note=y|narrow-percent=75}}

{{Species table/row
|name= Common merganser|binomial=[[Mergus merganser]]
|image=File:Birds of Sweden 2016 10.jpg|image-size=180px |image-alt=|image-caption=Male
|image2 =File:Mergus merganser fem.jpg|image2-caption=Female
|authority-name=Linnaeus |authority-year=1758 |authority-not-original=
|range= Europe, northern and central Asia, and North America
|range-image=File:MergusMerganserIUCNver2019-2.png
|range-image-size=180px
|size=
|habitat=
|hunting=
|iucn-status= LC
|population=
|direction=
|subspecies={{Collapsible list |expand=yes |title=Three subspecies |bullets=on
| ''M. m. merganser'' – <small>[[Carl Linnaeus|Linnaeus]], 1758</small> 
| ''M. m. orientalis'' – <small>[[John Gould|Gould]], 1845</small> 
| ''M. m. americanus'' – <small>[[John Cassin|Cassin]], 1852</small>
}}
}}

{{Species table/row
|name=Brazilian merganser |binomial=[[Mergus octosetaceus]]
|image=File:Mergus octosetaceus, morčák paranský, Zoo Praha.jpg|image-size=180px |image-alt=
|authority-name=Vieillot |authority-year=1817 |authority-not-original=
|range= Brazil
|range-image=File:Mergus octosetaceus map.svg
|range-image-size=180px
|size=
|habitat=
|hunting=
|iucn-status= CR
|population=
|direction=
|subspecies=
}}

{{Species table/row
|name=Red-breasted merganser |binomial=[[Mergus serrator]]
|image=File:Merganser (53630992394).jpg|image-size=180px |image-alt=|image-caption=Male
|image2 =File:Red-breasted Merganser (Mergus serrator).jpg|image2-caption=Female
|authority-name=Linnaeus |authority-year=1758 |authority-not-original=
|range= Northern North America, Greenland, Europe, and Asia
|range-image=File:MergusSerratorIUCN2018 2.png
|range-image-size=180px
|size=
|habitat=
|hunting=
|iucn-status= LC
|population=
|direction=
|subspecies=
}}

{{Species table/row
|name=Scaly-sided merganser |binomial=[[Mergus squamatus]]
|image=File:253 Schuppensäger 2009123ß.JPG|image-size=180px |image-alt=|image-caption=Male
|image2 =File:Scaly-sided merganser.jpg|image2-caption=Female
|authority-name=Gould|authority-year= 1864 |authority-not-original=
|range= East Asia
|range-image=
|range-image-size=180px
|size=
|habitat=
|hunting=
|iucn-status=EN
|population=
|direction=
|subspecies=
}}

{{Species table/end}}



{|class="wikitable"
! Image !! Scientific name !! Common name!! Distribution
|-
|[[File:MA I156484 TePapa Mergus-australis.jpg|120px]]
|†''Mergus australis''
|[[Auckland Island merganser]]
|[[Auckland Islands]], New Zealand (extinct {{Circa|1902}}). The species identity of merganser bones from mainland New Zealand—[[North Island|North]], [[South Island|South]], and [[Stewart Island|Stewart]] Islands—is unresolved.<ref name=":02">Miskelly, Colin & Forsdick, Natalie & Gill, Brian & Palma, Ricardo & Rawlence, Nicolas & Tennyson, Alan. (2022). CHECKLIST OF THE BIRDS OF NEW ZEALAND. https://www.researchgate.net/publication/361824003_CHECKLIST_OF_THE_BIRDS_OF_NEW_ZEALAND</ref>
|-
|
|†''Mergus milleneri''
|[[Mergus milleneri|Chatham Island merganser]]
|[[Chatham Island]], New Zealand. Extinct sometime after human settlement of the Chatham Islands,<ref name=":0" /> which began c.&nbsp;1500.<ref>{{Cite web |title=Moriori {{!}} people {{!}} Britannica |url=https://www.britannica.com/topic/Moriori |access-date=2022-05-30 |website=www.britannica.com |language=en}}</ref> 
|-
|}

=== Fossil species ===
Some [[fossil]] members of this genus have been described:
* ''Mergus miscellus'' is known from the Middle [[Miocene]] [[Calvert Formation]] ([[Barstovian]], c.&nbsp;14&nbsp;[[million years ago]]) of [[Virginia]], [[United States|USA]].<ref>{{cite journal | author1=Alvarez, R. | author2=Olson, S.L. | journal=Proceedings of the Biological Society of Washington | title=A New Merganser From The Miocene Of Virginia (Aves: Anatidae | volume=91 | pages=522–532 | date= 1978 | url=https://www.biodiversitylibrary.org/part/45680}}</ref>
* ''Mergus connectens'' lived in the [[Early Pleistocene]] about 2–1&nbsp;million years ago, in Central and Eastern Europe.<ref name="Mlikovsky2002a" />

The Early [[Oligocene]] [[booby]] ''"Sula" ronzoni'' was at first mistakenly believed to be a typical merganser.<ref>Mlíkovský (2002b): p. 264</ref> A Late [[Serravallian]] (13–12&nbsp;million years ago) fossil sometimes attributed to ''Mergus'', found in the [[Sajóvölgyi Formation]] of [[Mátraszőlős]], [[Hungary]], probably belongs to ''Mergellus''.<ref name="Gal" /> The affiliations of ''"Anas" albae'' from the [[Messinian]] (c. 7–5 million years ago) of Hungary are undetermined; it was initially believed to be a typical merganser too.<ref>Mlíkovský (2002b): p. 124</ref>

==References==
{{Reflist|refs=
<ref name=Arnott>[[Etymology]]: [[Latin]] ''mergus'', a catch-all term for sea-going birds: {{cite journal|author=Arnott, W.G. |year=1964|title= Notes on ''Gavia'' and ''Mergvs'' in Latin Authors|journal=Classical Quarterly |series=New Series |volume=14|issue=2|pages= 249–262|jstor=637729|doi=10.1017/S0009838800023806 |s2cid=170648873 }}</ref>
<ref name=Gal>{{cite journal|author1=Gál, Erika|author2=Hír, János|author3=Kessler, Eugén|author4=Kókay, József|name-list-style=amp|year=1998–99|title=Középsõ-miocén õsmaradványok, a Mátraszõlõs, Rákóczi-kápolna alatti útbevágásból. I. A Mátraszõlõs 1. lelõhely [Middle Miocene fossils from the sections at the Rákóczi chapel at Mátraszőlős. Locality Mátraszõlõs I.]|journal=Folia Historico Naturalia Musei Matraensis|volume=23|pages=33–78|language=Hungarian, English|url=http://www.matramuzeum.hu/Personal/folia/23/03MATSZOLOS.PDF|access-date=2007-02-06|archive-url=https://web.archive.org/web/20110721111701/http://www.matramuzeum.hu/Personal/folia/23/03MATSZOLOS.PDF|archive-date=2011-07-21|url-status=dead}}</ref><ref name=Livezey>{{cite journal|author=Livezey, Bradley C. |year=1986|title= A phylogenetic analysis of recent anseriform genera using morphological characters|journal=[[Auk (journal)|Auk]]|volume=103|issue=4|pages= 737–754|doi=10.1093/auk/103.4.737|url=http://sora.unm.edu/sites/default/files/journals/auk/v103n04/p0737-p0754.pdf}}</ref>
<ref name=Mlikovsky2002a>{{cite journal|author=Mlíkovský, Jirí|year=2002a|title=Early Pleistocene birds of Stránská skála, Czech Republic: 2. Absolon's cave|journal=Sylvia|volume=38|pages=19–28|url=http://www.nm.cz/download/JML-11-2002-stranska-skala.pdf|access-date=2008-08-05|archive-url=https://web.archive.org/web/20160411211257/http://www.nm.cz/download/JML-11-2002-stranska-skala.pdf|archive-date=2016-04-11|url-status=dead}}</ref>
}}

==Further reading==
* Mlíkovský, Jirí (2002b): [https://web.archive.org/web/20110520101755/http://www.nm.cz/download/JML-18-2002-CBE.pdf ''Cenozoic Birds of the World, Part 1: Europe'']. Ninox Press, Prague.<!-- This should be treated with extreme caution as regards merging of species. Splits are usually good though. See also critical review in Auk121:623–627 here http://www.findarticles.com/p/articles/mi_qa3793/is_200404/ai_n9396879 -->

{{Odontoanserae|B.|state=collapsed}}
{{Taxonbar|from=Q253789}}

[[Category:Mergus| ]]
[[Category:Bird genera]]
[[Category:Mergansers| ]]
[[Category:Langhian first appearances]]
[[Category:Extant Miocene first appearances]]
[[Category:Animal taxa named by Carl Linnaeus]]