Editing Greater scaup

{{Short description|Species of bird}}
{{Good article}}
{{Speciesbox
| name = Greater scaup
| fossil_range = {{Fossil range|Pleistocene|Recent|ref=<ref name="University of Michigan"/>}}
| image = Drake Greater scaup (Aythya marila) Barnegat Inlet, New Jersey, USA.jpg
| image2 = Hen greater scaup (Aythya marila) Barnegat Inlet, New Jersey, USA.jpg
| image_caption = A Greater Scaup in the [[Barnegat Inlet]].
| image2_caption = Female, [[Barnegat Inlet]]
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 11 November 2021">{{cite iucn |author=BirdLife International |date=2018 |title=''Aythya marila'' |volume=2018 |page=e.T22680398A132525108 |doi=10.2305/IUCN.UK.2018-2.RLTS.T22680398A132525108.en |access-date=11 November 2021}}</ref>
| genus = Aythya
| species = marila
| authority = ([[Carl Linnaeus|Linnaeus]], 1761)
| subdivision_ranks = Subspecies
| subdivision =
''A. m. marila'' <small>(Linnaeus, 1761)</small><br/> <small>(Eurasian greater scaup)</small><br/>
''A. m. nearctica'' <small>([[Leonhard Hess Stejneger|Stejneger]], 1885)</small><br/> <small>(Nearctic greater scaup)</small>
| range_map = The GS range map.jpg
| range_map_caption = Range of ''Aythya marila''
| synonyms = ''Anas marila'' {{small|Linnaeus,&nbsp;1761}}
}}
{{birdsong|url=https://xeno-canto.org/species/Aythya-marila|species=Greater Scaup}}

The '''greater scaup''' ('''''Aythya marila'''''), just '''scaup''' in Europe or, colloquially, "bluebill" in North America,<ref name="Bluebills"/> is a mid-sized [[diving duck]], larger than the closely related [[lesser scaup]] and [[tufted duck]]. It spends the summer months breeding in [[Iceland]], east across [[Scandinavia]], northern [[Russia]] and [[Siberia]], [[Alaska]], and northern [[Canada]]. During the winter, it [[bird migration|migrates]] south to the coasts of Europe, eastern Asia, and North America.

[[Duck|Drake]] greater scaup are larger and have more rounded heads than the females; they have a bright blue bill and yellow eyes. Their heads are dark, with a green to purple (depending on light angle) gloss; the breast is black, the belly white, the upperparts pale grey, and the wing shows a strong white stripe. The females are mostly brown, again with white on the wing. They have dull blue bills and a white patch on the face.

Greater scaup nest near water, typically on islands in northern lakes or on floating mats of vegetation. They begin breeding at age two, but start building nests in the first year. The drakes have a complex [[Courtship display|courtship]], which takes place on the return migration to the summer breeding grounds and concludes with the formation of [[Monogamy in animals|monogamous]] pairs. Females lay a [[clutch (eggs)|clutch]] of six to nine olive-buff-coloured eggs. The eggs hatch in 24 to 28 days. The [[down feather|down]]-covered ducklings are able to follow their mother in her search for food immediately after hatching.

Greater scaup eat aquatic [[molluscs]], plants, and insects, which they obtain by diving underwater to depths of 0.5–6 m, exceptionally 10 m.<ref name=BWP>{{ cite book | editor1-last=Cramp | editor1-first=Stanley | editor1-link=Stanley Cramp | year=1977 | chapter=''Aythya marila'' Scaup | title=Handbook of the Birds of Europe the Middle East and North Africa. The Birds of the Western Palearctic | volume=I: Ostrich to Ducks | location=Oxford | publisher=Oxford University Press | isbn=978-0-19-857358-6 | pages=586–593 }}</ref> They form large groups, called "rafts", that can number in the thousands. Their main threat is human development, although they are also preyed upon by owls, skunks, raccoons, foxes, coyotes, and humans. Greater scaup populations have been declining since the 1980s; however, they are still listed as a species of least concern on the [[IUCN Red List]].<ref name="iucn status 11 November 2021" />

==Taxonomy==
[[File:Greater-scaup-male2.jpg|thumb|left|''A. m. nearctica'' male, California]]
The greater scaup was [[species description|formally described]] by [[Carl Linnaeus]] in 1761 under the [[binomial name]] ''Anas marila''. The [[type locality (biology)|type locality]] is Lapland.<ref>{{cite book | last=Linnaeus | first=Carl | author-link=Carl Linnaeus | year=1761 | title=Fauna svecica, sistens animalia sveciae regni mammalia, aves amphibia, pisces, insecta, vermes | edition=2nd | language=la | location=Stockholmiae | publisher=Sumtu & Literis Direct. Laurentii Salvii | page=39 | url=https://www.biodiversitylibrary.org/page/32170508 }}</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=486 | url=https://www.biodiversitylibrary.org/page/16109126 }}</ref> The species is now placed in the [[genus]] ''[[Aythya]]'' that was introduced for the greater scaup by the German zoologist [[Friedrich Boie]] in 1822.<ref>{{ cite book | last=Boie | first=Friedrich | author-link=Friedrich Boie | year=1822 | title=Tagebuch gehalten auf einer Reise durch Norwegen im Jahre 1817 | language=de | publisher=Schleswig | pages=[https://archive.org/details/tagebuchgehalten00boie/page/308 308], 351 | url=https://archive.org/details/tagebuchgehalten00boie }}</ref><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 | year=2020 | title=Screamers, ducks, geese, swans | work=IOC World Bird List Version 10.1 | url=https://www.worldbirdnames.org/bow/waterfowl/ | publisher=International Ornithologists' Union | access-date=23 March 2020 }}</ref>

The genus name ''Aythya'' is derived from the [[Ancient Greek]] {{lang|grc|αἴθυιᾰ}} ({{Transliteration|grc|aithuia}}) which refers to a seabird mentioned by [[Aristotle]] and others and is thought to refer to a seaduck or other seabird. The species name ''marila'' is from the Greek word for charcoal embers or coal dust.<ref name=Jobling2010/>

[[File:Aythya marila f Humber Bay Toronto.jpg|thumb|left|''A. m. nearctica'' female, Ontario]]
Two subspecies of Greater scaup are currently accepted. The nominate ''A. m. marila'' is found from northern Europe to east Siberia, west of the [[Lena River]]. The birds in North America are treated as a separate subspecies ''A. m. nearctica'',<ref name="Reeber" /> and are distinguishable from those in Europe by a typically higher forehead, and the male having stronger vermiculations on the mantle and [[scapula]]rs. Additionally, there is less extensive white on the primary feathers than ''A. m. marila''.<ref name="Sangster2005" /> Greater Scaup of far eastern Asia (east of the Lena River towards the Bering Sea) are intermediate between the two subspecies and sometimes lumped with either race, or a distinct subspecies ''A. m. mariloides'', though the latter name is invalid, as it was first used to describe the lesser scaup ''A. affinis''.<ref name="Banks1986" /> Based on size differences, a [[Pleistocene]] [[paleosubspecies]], ''Aythya marila asphaltica'', has also been described by Serebrovskij in 1941 from [[fossil]]s recovered at [[Binagady]], Azerbaijan. A [[phylogenetic]] analysis of the diving ducks, examining the skeletal anatomy and skin, found that the greater and lesser scaups are each other's closest relatives, with the [[tufted duck]] as the next closest relative of the pair.<ref name=Livezey1996/>

The greater scaup's English name, first attested as 'Scaup Duck' in 1678, most likely comes from "scaup" or "scalp", a [[Scots language|Scottish]] and [[Northern England English|Northern English]] word for a shellfish bed, where the birds typically feed in winter.<ref name="Lockwood">{{cite book|last = Lockwood| first = W. B.|title = Oxford Book of British Bird Names|publisher = Oxford University Press|year = 1984}}</ref><ref name="NSOED" /> but could also be from the duck's [[mating call]]: "scaup scaup".{{citation needed|date=August 2024}}

[[File:GScaup27122021.png|thumb|Comparison photo: Greater scaup (top left) vs. [[Tufted duck]] (''Aythya fuligula'')]]

==Description==
The adult greater scaup is {{convert|39|–|56|cm|abbr=on}} long with a {{convert|71|–|84|cm|in|abbr=on}} wingspan and a weight of {{convert|726|-|1360|g|lb|abbr=on}}. It has a light blue bill with a small black [[Beak#Nail|nail]] on the tip, yellow eyes, and is 20% heavier and 10% longer than the closely related lesser scaup.<ref name=Birdweb/> The male has a dark head with a green to purple sheen, a black breast, a light back, a black tail, and a white underside. The drake or male is larger and has a more rounded head than the female. The drake's belly and flanks are a bright white. Its neck, breast, and tail feathers are glossy black, while its lower flanks are [[vermiculated]] grey. The upper wing has a white stripe starting as the [[speculum feathers|speculum]] and extending along the flight feathers to the wingtip. Legs and feet of both sexes are grey.

The adult female has a brown body and head, with white wing markings similar to those of the male but slightly duller. It has a white band and brown oval shaped patches at the base of the bill, which is a slightly duller shade of blue than the drake's.<ref name="DucksUnlimited" /> Juvenile greater scaup look similar to adult females. The drake's [[Plumage#Eclipse plumage|eclipse plumage]] looks similar to its breeding plumage, except the pale parts of the plumage are a buffy grey.<ref name="enature" />

Distinguishing greater from lesser scaups can be difficult in the field. The head of the greater tends to be more rounded, and the white wing stripe is more extensive. The bill is also tends to be larger and wider, with a slightly larger black nail at the tip. The North American subspecies ''A. m. nearctica'' typically has a higher forehead and reduced white on the wings, intermediate between the European ''A. m. marila'' and Lesser Scaup.<ref name="Birdweb" />

==Distribution and habitat==
The greater scaup has a circumpolar distribution, breeding within the Arctic Circle both in the Old World (the [[Palearctic realm|Palearctic]]) and in North America (the [[Nearctic realm|Nearctic]]). It spends the summer months in [[Iceland]], east across [[Scandinavia]], northern [[Russia]] and [[Siberia]], [[Alaska]], and northern [[Canada]]. It is mostly migratory, but small numbers are present in Iceland and the [[Aleutian Islands]] year round.<ref name=Birdlife/> The summer habitat is marshy lowland [[tundra]] and islands in fresh water lakes. In the autumn, greater scaup populations start their migration south for the winter. They winter along the Pacific and Atlantic coasts of North America, the coasts of northwest Europe, the [[Caspian Sea]], the [[Black Sea]], the coast of Japan, [[Yellow Sea]] and [[East China Sea]].<ref name=EuropeBirdguide/> During the winter months, they are found in coastal bays, [[estuaries]], and sometimes inland lakes,<ref name=BirdsNorthAmerica/> such as the lakes of [[Central Europe]] and the [[Great Lakes]].<ref name=EuropeBirdguide/>

In Europe, the greater scaup breeds in Iceland, the northern coasts of the [[Scandinavian Peninsula]], including much of the northern parts of the [[Baltic Sea]], the higher mountains of Scandinavia and the areas close to the [[Arctic Sea]] in Russia. It has also bred sporadically in northern [[Scotland]].<ref name=BWP/> These birds spend the winters in the [[British Isles]], western Norway, the southern tip of Sweden, the coast from [[Brittany]] to Poland, including all of Denmark, the Alps, the eastern [[Adriatic Sea]], the northern and western Black sea and the southwestern Caspian Sea.<ref name=Ullman1992/><ref name=Delin2001/>

In North America, the greater scaup summers in [[Newfoundland and Labrador]], [[Ungava Bay]], [[Hudson Bay]], [[Lake Winnipeg]], northern [[Yukon]], northern [[Manitoba]], and northern [[Saskatchewan]]. It winters along the coasts of North America from northern [[British Columbia]] south to the [[Baja Peninsula]] and from [[Nova Scotia]] and [[New Brunswick]] south to [[Florida]], as well as the shores of the Great Lakes and the Gulf of Mexico.<ref name=EuropeBirdguide/>

==Behaviour==

===Breeding===
[[File:Aythya marila MWNH 1032.JPG|thumb|Egg, Collection [[Museum Wiesbaden]]]]
Greater scaup breed in the tundra and the [[boreal forest]]; it is estimated that 75% of the North American population breed in Alaska. They typically nest on islands in large northern lakes. Greater scaup begin breeding when they are two years old, although they may start nesting at age one. Drake greater scaup have a soft, quick whistle they use to attract the attention of hens during courtship, which takes place from late winter to early spring, on the way back to their northern breeding grounds. Female greater scaup have a single pitch, a raspy "arrr-arrr-arrr-arrr-arrr" call note.<ref name="Greater Scaup"/> The courtship is complex and results in the formation of monogamous pairs.<ref name=Utahwildlife/>

Pairs nest in close proximity to each other in large colonies, usually near water, on an island or shoreline, or on a raft of floating vegetation. The nest consists of a shallow depression made by the female and lined with her down.<ref name="Birdweb" /> After the female lays the eggs, the drake abandons the female<ref name="Utahwildlife" /> and goes with other drakes to a large, isolated lake to moult. These lakes can be close to the breeding grounds, or distant, with birds performing a [[bird migration|moult migration]] of up to several hundred km, such as from northern Scandinavia to the [[IJsselmeer]] in the Netherlands.<ref name=BWP/> The lakes chosen are used yearly by the same ducks. The optimal moulting lake is fairly shallow and has an abundance of food sources and cover.<ref name="All about birds" />

The female lays six to nine olive-buff-coloured eggs,<ref name="Audubonbirds" /> which she [[egg incubation|incubates]] for 24–28 days.<ref name="Ohio.gov" /> A larger clutch could indicate [[brood parasitism]] by other greater scaups or even ducks of other species.<ref name="Fournier2001" /> The newly hatched ducklings are covered with down and are soon able to walk, swim, and feed themselves; however, they are not able to fly until 40–45 days after hatching.<ref name="EuropeBirdguide" /><ref name="Utahwildlife" /> The vulnerable small ducklings follow their mother, who protects them from predators.<ref name="Utahwildlife" />

===Feeding===
[[File:Aythya marila4.jpg|thumb|Flock feeding in Tokyo bay, Japan]]
The greater scaup dive to obtain food, which they eat on the surface.<ref name=Birdweb/> They mainly eat [[mollusc]]s, aquatic plants, and aquatic insects.<ref name="Greater Scaup"/> During the summer months, the greater scaup will eat small aquatic [[crustacean]]s.<ref name=Birdweb/> There is a report of four greater scaups in April near Chicago swallowing hibernating [[leopard frog]]s (a species with a body length about 5 centimetres, or 2.0 in), which they dredged out of a roadside freshwater pond.<ref name=Longley1948/> In freshwater [[ecosystem]]s, the greater scaup will eat seeds, leaves, stems and roots, along with sedges, pondweeds, [[muskgrass]], and [[Vallisneria americana|American eelgrass]].<ref name=DucksUnlimited/> Owing to the greater scaup's webbed feet and weight, it can dive up to {{convert|6–10|m|ft|sigfig=1}} and stay submerged for up to a minute.<ref name=Feeding/> In the past, they also often fed in winter in huge flocks on spent grain pumped offshore from distilleries (notably in the [[Firth of Forth]] in Scotland), but with modern pollution control, this food source is no longer available.<ref name=BWP/><ref name=Lack>{{ cite book |title=The Atlas of Wintering Birds in Britain and Ireland |editor-first=Peter |editor-last=Lack |first=L. H. |last=Campbell |chapter=Tufted Duck |year=1986 |location=London, UK |publisher=T & AD Poyser |page=112 |isbn=978-1-4081-3828-1 }}</ref>

==Threats==
[[File:Zwemmende toppereenden-4961904.webm|thumb|Video of greater scaup.]]
Common predators of the greater scaup are [[owls]], [[fox]]es, [[skunk]]s, [[raccoon]]s, [[coyote]]s, and humans.<ref name=USFauna/> Greater scaup often become entangled in fishing nets, and large numbers of them drown in this way each year. Greater scaup can catch [[avian influenza]], so future outbreaks have the potential to threaten their populations.<ref name=Birdlife/>

Although the greater scaup faces numerous threats, the most significant challenge to their survival is habitat degradation caused by a mix of human development and runoff.<ref name=NBII/> Greater scaup, when moulting and during the winter, are threatened by escalated levels of organochloride contaminants. Oil and sewage pollution also threaten this duck. Since 80% of the greater scaup population winters in the urbanised part of the [[Atlantic Flyway]], these ducks are subject to high levels of organic contaminants, along with increased levels of heavy metals in foods and habitat.<ref name=BirdsNorthAmerica/>

A joint group of American and Canadian scientists researching scaup migration across the Great Lakes found that 100% of female greater scaup and 77% of female lesser scaup had escalated levels of [[selenium]] in their bodies. Selenium is a [[semimetal]]lic [[trace element]] that occurs naturally in some soils; minute amounts of it are necessary for animal life. However, excessive selenium can cause reproductive harm and is highly toxic. On their migration across the Great Lakes, greater scaups are at risk of ingesting selenium by eating the invasive [[zebra mussels]], which can render the female scaup [[infertile]].<ref name=Bluebills/> This sterilization is causing the population to decrease.

In a study of 107 scaup, they all had traces of [[iron]], [[zinc]], [[manganese]], [[copper]], [[lead]], [[cadmium]], [[cobalt]] and [[nickel]] in their tissue samples with varying concentrations of metals in different types of tissues. The kidneys had the highest levels of cadmium, the liver had the highest levels of copper and manganese, the liver and the stomach had the highest levels of zinc, and the lungs and liver had the highest levels of iron.<ref name="Trace metals in the soft tissues of scaup"/> There was no difference in concentrations when comparing sexes.

==Conservation==
Greater scaup are rated as a species of least concern by the IUCN Redlist.<ref name="iucn status 11 November 2021" /> During aerial population surveys greater and lesser scaup are counted together, because they look almost identical from the air. It was estimated that the greater scaup made up about 11% of the continental scaup population. Since the 1980s, scaup populations have been steadily decreasing. Some of the primary factors contributing to this decline are [[habitat loss]], contaminants, changes in breeding habitat, and a lower female survival rate. The 2010 American scaup population survey was 4.2&nbsp;million scaup,<ref name=USFWS/> however, the worldwide greater scaup population survey estimated 1,200,000 to 1,400,000 mature greater scaup.<ref name=Birdlife/> Along with the aerial population surveys, there is a [[bird ringing|ringing programme]] for the greater scaup. Metal leg bands are placed on them, so that if the scaup is killed by a hunter or if it is captured by another ringing group, the number on the band can be reported to biologists and wildlife organisations. These ringing programmes yield valuable data about migration patterns, harvest rates, and survival rates.<ref name=FlywaysUS/>

[[File:Greater scaup decoys.jpg|thumb|Greater scaup decoys, male on the left and female on the right. Each is attached to a lead weight.]]

==Human interactions==
Greater scaup are a popular [[game bird]] in North America and Europe.<ref name=eumanagement/> They are hunted in Denmark, Germany, Greece, France, the United Kingdom, and Ireland,<ref name=eumanagement/> and in Iran for both sport and commercial reasons.<ref name=EuropeBirdguide/> Greater scaup are hunted with [[shotguns]] because they must be shot on the fly, a challenging task, as they can fly at up to {{convert|121|km/h|mph|abbr=on}}. Greater scaup are hunted from shorelines and in open water [[hunting blind]]s or [[layout boat]]s, low-profile [[kayak]]-like boats that hunters lie inside. Hunters frequently use [[decoy]]s to attract the birds, often arranged to simulate a raft of greater scaup and featuring an open area to attract the birds to land.<ref name=discoveroutdoors/>

==References==
{{Reflist|colwidth=33em|refs=
<ref name="All about birds">{{Cite AllAboutBirds|Greater Scaup |access-date=18 December 2011}}</ref>

<ref name=Audubonbirds>{{cite web |url=http://www.audubonbirds.org/species/Birds/Greater-Scaup.html |title=Greater Scaup |access-date=27 November 2011 |publisher=National Audubon Society, Inc. |url-status=dead |archive-url=https://web.archive.org/web/20120425081000/http://www.audubonbirds.org/species/Birds/Greater-Scaup.html |archive-date=25 April 2012 }}</ref>

<ref name=Banks1986>{{cite journal |last=Banks |first=R.C. |year=1986 |title=Subspecies of the Greater Scaup and their names |journal=Wilson Bulletin |volume=98 |issue=3 |pages=433–444 |url=http://sora.unm.edu/sites/default/files/journals/wilson/v098n03/p0433-p0444.pdf}}</ref>

<ref name=Birdlife>{{cite web |url=http://www.birdlife.org/datazone/species/factsheet/22680398 |title=Greater Scaup ''Aythya marila'' |access-date=9 March 2015 |publisher=Bird Life International}}</ref>

<ref name=BirdsNorthAmerica>{{cite web |url=http://bna.birds.cornell.edu/bna/species/650/articles/introduction |title=Greater Scaup |access-date=2 January 2011 |work=The Birds of North America |publisher=Cornell Lab of Ornithology}}</ref>

<ref name=Birdweb>{{cite web |url=http://www.birdweb.org/birdweb/bird/greater_scaup |title=Greater Scaup |access-date=26 October 2011 |work=Bird Web |publisher=Seattle Audubon Society}}</ref>

<ref name=Bluebills>{{cite web |url=http://www.dnr.state.mn.us/volunteer/sepoct07/bluebills.html |title=Bluebills |access-date=3 November 2011 |publisher=Minnesota Department of Natural Resources |archive-url=https://web.archive.org/web/20131220160024/http://www.dnr.state.mn.us/volunteer/sepoct07/bluebills.html |archive-date=20 December 2013 |url-status=dead}}</ref>

<ref name=Delin2001>{{cite book |last1=Delin |first1=Håkan |title=Färgfotoguiden över alla Europas fåglar |trans-title=Colour Photo Guide of European Birds |language=sv |publisher=Bonniers |year=2001 |isbn=978-91-34-51940-4 |page=50}}</ref>

<ref name=discoveroutdoors>{{cite web |url=http://www.dto.com/hunting/speciesProfile/118 |title=Greater Scaup |access-date=19 November 2011 |publisher=Discover the Outdoors}}</ref>

<ref name=DucksUnlimited>{{cite web |url=http://www.ducks.org/hunting/waterfowl-id/greater-scaup |title=Greater Scaup |access-date=1 November 2011 |publisher=Ducks Unlimited}}</ref>

<ref name=enature>{{cite web |url=http://www.enature.com/fieldguides/detail.asp?recNum=BD0403 |title=Greater Scaup |access-date=11 December 2011 |website=enature.com |archive-url=https://web.archive.org/web/20120212205500/http://www.enature.com/fieldguides/detail.asp?recnum=BD0403 |archive-date=12 February 2012 |url-status=dead }}</ref>

<ref name=eumanagement>{{cite web |url=http://ec.europa.eu/environment/nature/conservation/wildbirds/hunting/docs/Scaup%20EU_MP.pdf |title=European Union Management Plan |access-date=2 November 2011 |work=EU |publisher=European Union}}</ref>

<ref name=EuropeBirdguide>{{cite web |url=http://www.avibirds.com/euhtml/Greater_Scaup.html |title=Greater Scaup |access-date=8 November 2011 |publisher=Avibirds European birdguide online}}</ref>

<ref name=Feeding>{{cite web |url=http://birds.audubon.org/species/gresca |title=Greater Scaup |access-date=26 October 2011 |work=Audubon |publisher=National Audubon Society |archive-url=https://web.archive.org/web/20101111062850/http://www.audubon.org/species/gresca |archive-date=11 November 2010 |url-status=dead}}</ref>

<ref name=FlywaysUS>{{cite web |url=http://www.flyways.us/surveys-and-monitoring/banding-and-marking-programs |title=Banding and Marking Programs |publisher=U.S. Fish and Wildlife Service |access-date=28 November 2011 |archive-date=20 January 2012 |archive-url=https://web.archive.org/web/20120120191531/http://www.flyways.us/surveys-and-monitoring/banding-and-marking-programs |url-status=dead }}</ref>

<ref name=Fournier2001>{{cite journal |journal=Arctic |volume=54 |issue=4 |year=2001 |pages=444–456 |title=Breeding Ecology of Sympatric Greater and Lesser Scaup (Aythya marila and Aythya affinis) in the Subarctic Northwest Territories |last1=Fournier |first1=M.A. |first2=J.E. |last2=Hines |url=http://arctic.synergiesprairies.ca/arctic/index.php/arctic/article/viewFile/801/827 |doi=10.14430/arctic801 |url-status=dead |archive-url=https://web.archive.org/web/20120425122322/http://arctic.synergiesprairies.ca/arctic/index.php/arctic/article/viewFile/801/827 |archive-date=2012-04-25 |citeseerx=10.1.1.487.6171 }}</ref>

<ref name="Greater Scaup">{{cite web |last=Mayntz |first=Melissa |url=http://birding.about.com/od/birdprofiles/p/greaterscaup.htm |title=Greater Scaup |access-date=20 August 2011 |publisher=About.com |archive-url=https://web.archive.org/web/20100310024016/http://birding.about.com/od/birdprofiles/p/greaterscaup.htm |archive-date=10 March 2010 |url-status=dead }}</ref>

<ref name=Jobling2010>{{cite book |last= Jobling |first=James A. |pages=[https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling/page/n64 64], 242 |year=2010 |isbn=978-1-4081-2501-4 |publisher=Christopher Helm |place=London |title=The Helm Dictionary of Scientific Bird Names|url= https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling }}</ref>

<ref name=Livezey1996>{{cite journal |last=Livezey |first=Bradley C. |year=1996 |title=A phylogenetic analysis of modern pochards (Anatidae: Aythyini) |journal=The Auk |volume=113 |issue=1 |pages=74–93 |url=http://sora.unm.edu/sites/default/files/journals/auk/v113n01/p0074-p0093.pdf |doi=10.2307/4088937|jstor=4088937 }}</ref>

<ref name=Longley1948>{{cite journal |last=Longley |first=William H. |url=http://sora.unm.edu/sites/default/files/journals/auk/v066n02/p0200-p0200.pdf |title=Greater scaup eating frogs |year=1948 |journal=The Auk |volume=66 |issue=2 |page=200}}</ref>

<ref name=NBII>{{cite web |url=http://www.nbii.gov/portal/server.pt/community/greater_scaup/1664 |title=Greater Scaup |access-date=8 November 2011 |publisher=National Biological Information Infrastructure |archive-url=https://web.archive.org/web/20111209213826/http://www.nbii.gov/portal/server.pt/community/greater_scaup/1664 |archive-date=9 December 2011 |url-status=dead}}</ref>

<ref name=NSOED>{{cite book |title=New Shorter Oxford English Dictionary |publisher=Oxford University Press |year=1993 |isbn=978-0-19-861271-1 |url-access=registration |url=https://archive.org/details/newshorteroxford00lesl }}</ref>

<ref name=Ohio.gov>{{cite web |url=http://wildlife.ohiodnr.gov/species-and-habitats/species-guide-index/birds/greater-scaup |title=Greater Scaup |access-date=9 March 2015 |publisher=Ohio Department of Natural Resources}}</ref>

<ref name=Reeber>{{cite book |last1=Reeber |first1=Sébastien |title=Waterfowl of North America, Europe, and Asia : an identification guide |date=2015 |publisher=Princeton University Press |location=Princeton, NJ |isbn=978-0691162669 }}</ref>

<ref name=Sangster2005>{{citation |last1=Sangster |first1=George |last2=Collinson |first2=J. Martin |last3=Helbig |first3=Andreas J. |last4=Knox |first4=Alan G. |last5=Parkin |first5=David T. |title=Taxonomic recommendations for British birds: third report |journal=Ibis |volume=147 |issue=4 |pages=821–826 |year=2005 |doi=10.1111/j.1474-919X.2005.00483.x|s2cid=250043960 |doi-access=free }}</ref>

<ref name="Trace metals in the soft tissues of scaup">{{cite journal |first1=Piotr |last1=Szefer |first2=Jerzy |last2=Falandysz |title=Trace metals in the soft tissues of scaup ducks (Aythya marila L.) wintering in Gdańsk bay, Baltic sea |journal=Science of the Total Environment |year=1987 |volume=65 |pages=203–213 |doi=10.1016/0048-9697(87)90173-2|bibcode=1987ScTEn..65..203S }}</ref>

<ref name=Ullman1992>{{Cite book |last=Ullman |first=Magnus |title=Fåglar i Europa |trans-title=Birds in Europe |language=sv |publisher=Wahlström & Widstrand |year=1992 |isbn=978-91-46-17633-6 |page=102}}</ref>

<ref name="University of Michigan">{{cite journal |last1=Alvarez |first1=Rafael |title=A pleistocene avifauna from Jalisco, Mexico |journal=Contributions from the Museum of Paleontology, University of Michigan |volume=24 |number=19 |publisher=University of Michigan |url=http://deepblue.lib.umich.edu/bitstream/handle/2027.42/48486/ID336.pdf?sequence=2&isAllowed=y |page=214 |year=1977 |access-date=9 March 2015 }}</ref>

<ref name=USFauna>{{cite web |url=http://www.unitedstatesfauna.com/greaterscaup.php |title=Greater Scaup |access-date=2 November 2011 |publisher=United States Fauna |archive-url=https://web.archive.org/web/20131021123232/http://www.unitedstatesfauna.com/greaterscaup.php |archive-date=21 October 2013 |url-status=dead}}</ref>

<ref name=USFWS>{{cite web |title=Waterfowl Hunting Management in North America |work=Scaup Population Estimates |publisher=U.S. Fish and Wildlife Service in collaboration with flyway and state waterfowl managers |date=29 June 2010 |url=http://www.flyways.us/status-of-waterfowl/population-estimates/scaup-population-estimates |access-date=4 November 2011 |archive-date=16 October 2011 |archive-url=https://web.archive.org/web/20111016034424/http://flyways.us/status-of-waterfowl/population-estimates/scaup-population-estimates |url-status=dead }}</ref>

<ref name=Utahwildlife>{{cite web |url=http://dwrcdc.nr.utah.gov/rsgis2/search/Display.asp?FlNm=aythmari |title=Greater Scaup |access-date=8 November 2011 |publisher=Utah Department of Natural Resources |archive-date=16 December 2016 |archive-url=https://web.archive.org/web/20161216171116/http://dwrcdc.nr.utah.gov/rsgis2/Search/Display.asp?FlNm=aythmari |url-status=dead }}</ref>
}}

==Further reading==
* {{cite journal |last=Collinson |first=Martin |url=http://www.britishbirds.co.uk/search?id=9283 |title=Splitting headaches? Recent taxonomic changes affecting the British and Western Palaearctic lists |journal=[[British Birds (magazine)|British Birds]] |volume=99 |date=June 2006 |pages=306–323}}
* {{cite book |last1=Madge |first1=Steve |last2=Burn |first2=Hilary |title=Wildfowl: An Identification Guide to the Ducks, Geese and Swans of the World |year=1988 |publisher=Christopher Helm |location=London |isbn=978-0-7470-2201-5}}

== External links ==
{{Commons category|Aythya marila}}
{{Wikispecies|Aythya marila}}
* [http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/Greater_Scaup.html Greater Scaup Species Account] – Cornell Lab of Ornithology
* [http://www.mbr-pwrc.usgs.gov/id/framlst/i1480id.html Greater Scaup - ''Aythya marila''] - USGS Patuxent Bird Identification InfoCenter
* {{InternetBirdCollection|greater-scaup-aythya-marila}}
* {{VIREO|Greater+Scaup}}

{{North American Game}}
{{Taxonbar|from=Q26635}}
{{Authority control}}

[[Category:Aythya|greater scaup]]
[[Category:Holarctic birds]]
[[Category:Birds described in 1761|greater scaup]]
[[Category:Extant Pleistocene first appearances]]
[[Category:Taxa named by Carl Linnaeus]]