Greater scaup

This is a good article. Click here for more information.
Source: Wikipedia, the free encyclopedia.

Greater scaup
Temporal range: Pleistocene–Recent[1]
↓
Adult male in California
Adult female in Ontario

Least Concern  (IUCN 3.1)[2]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Genus: Aythya
Species:
A. marila
Binomial name
Aythya marila
(Linnaeus, 1761)
Subspecies

A. m. marila (Linnaeus, 1761)
(Eurasian greater scaup)
A. m. nearctica (

Stejneger
, 1885)
(Nearctic greater scaup)

Range of Aythya marila
Synonyms

Anas marila Linnaeus, 1761

The greater scaup (Aythya marila), just scaup in Europe or, colloquially, "bluebill" in North America,[3] is a mid-sized diving duck, larger than the closely related lesser scaup. It spends the summer months breeding in Alaska, northern Canada, Siberia, and the northernmost reaches of Europe. During the winter, it migrates south to the coasts of North America, Europe, and Japan.

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 gloss; the breast is black, the belly white and the wing shows a white stripe. The females are mostly brown, again with white on the wing. They have dull blue bills and white 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, which takes place on the return migration to the summer breeding grounds and concludes with the formation of monogamous pairs. Females lay a clutch of six to nine olive-buff-colored eggs. The eggs hatch in 24 to 28 days. The 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. They form large groups, called "rafts", that can number in the thousands. Their main threat is human development, although they are 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.[2]

Taxonomy

The greater scaup was

type locality is Lapland.[4][5] The species is now placed in the genus Aythya that was introduced for the greater scaup by the German zoologist Friedrich Boie in 1822.[6][7]

The genus name Aythya is derived from the Ancient Greek aithuia which refers to a seabird mentioned by Aristotle and others and is thought to refer to a duck, auklet or other seabird. The species name marila is from the Greek word for charcoal embers or coal dust.[8]

At least two subspecies of Greater scaup are recognized. The nominate A. m. marila is found from northern Europe to east Siberia, west of the

Northern English word for a shellfish bed,[12] or from the duck's mating call
: "scaup scaup".

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.[13]

Comparison photo: Greater scaup (top left) vs. Tufted duck (Aythya fuligula)

Description

The adult greater scaup is 39–56 cm (15–22 in) long with a 71–84 cm (28–33 in) wingspan and a body mass of 726–1,360 g (1.601–2.998 lb). It has a blue bill and yellow eyes and is 20% heavier and 10% longer than the closely related lesser scaup.

vermiculated gray. The upper wing has a white stripe starting as the speculum
and extending along the flight feathers to the wingtip. Legs and feet of both sexes are gray.

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.[15] Juvenile greater scaup look similar to adult females. The greater scaup drake's eclipse plumage looks similar to its breeding plumage, except the pale parts of the plumage are a buffy gray.[16]

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, often with a large black nail at the tip. The North American subspecies nearctica typically has a higher forehead and reduced white on the wings, intermediate between the European marila and Lesser Scaup.[14]

Distribution and habitat

The greater scaup has a circumpolar distribution, breeding within the Arctic Circle both in the Old World (the

estuaries, and sometimes inland lakes,[19] such as the lakes of Central Europe and the Great Lakes.[18]

In Europe, the greater scaup breeds in Iceland, the northern coasts of the

Arctic Sea in Russia. 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.[20][21]

In North America, the greater scaup summers in

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.[18]

Behaviour

Breeding

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” vocalization.[22] The courtship is complex and results in the formation of monogamous pairs.[23]

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.[14] After the female lays the eggs, the drake abandons the female[23] and goes with other drakes to a large, isolated lake to molt. These lakes can be close to the breeding grounds or miles away. The lakes chosen are used yearly by the same ducks. The optimal molting lake is fairly shallow and has an abundance of food sources and cover.[24]

The female lays six to nine olive-buff-colored eggs,[25] which she incubates for 24–28 days.[26] A larger clutch could indicate brood parasitism by other greater scaups or even ducks of other species.[27] Newly hatched chicks 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.[18][23] The vulnerable small chicks follow their mother, who protects them from predators.[23]

Feeding

Flock feeding in Tokyo bay, Japan

The greater scaup dive to obtain food, which they eat on the surface.

muskgrass, and wild celery.[15] Owing to the greater scaup's webbed feet and weight, it can dive up to 6 metres (20 ft) and stay submerged for up to a minute, allowing it to reach food sources that are unobtainable to other diving ducks.[29]

Threats

Video of greater scaup.

Common predators of the greater scaup are

skunks, raccoons, foxes, coyotes, and humans.[30] Greater scaup often find themselves entangled in fishing nets, thus large numbers of them drown in nets each year. Greater scaup can catch avian influenza, so future outbreaks have the potential to threaten greater scaup populations.[17]

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.[31] 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 urbanized part of the Atlantic Flyway, these ducks are subject to high levels of organic contaminates, along with increased levels of heavy metals in foods and habitat.[19]

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

infertile.[3]
This sterilization of hens 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. Further analysis revealed that 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.[32] There was no difference in concentration when comparing genders.

Conservation

Greater scaup are rated as a species of least concern by the IUCN Redlist.

habitat loss, contaminants, changes in breeding habitat, and a lower female survival rate. The 2010 American scaup population survey was 4.2 million scaup,[33] however, the worldwide greater scaup population survey estimated 1,200,000 to 1,400,000 mature greater scaup.[17] Along with the aerial population surveys, there is a banding program 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 banding group, the number on the band can be reported to biologists and wildlife organizations. These banding programs yield valuable data about migration patterns, harvest rates, and survival rates.[34]

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

layout boats, low-profile kayak-like boats that hunters lie inside. Hunters frequently use decoys to attract the birds, often arranged to simulate a raft of greater scaup and featuring an open area to attract the birds to land.[36]

References

  1. ^ Alvarez, Rafael (1977). "A pleistocene avifauna from Jalisco, Mexico" (PDF). Contributions from the Museum of Paleontology, University of Michigan. 24 (19). University of Michigan: 214. Retrieved 9 March 2015.
  2. ^
    doi:10.2305/IUCN.UK.2018-2.RLTS.T22680398A132525108.en
    . Retrieved 11 November 2021.
  3. ^ a b "Bluebills". Minnesota Department of Natural Resources. Archived from the original on 20 December 2013. Retrieved 3 November 2011.
  4. ^ Linnaeus, Carl (1761). Fauna svecica, sistens animalia sveciae regni mammalia, aves amphibia, pisces, insecta, vermes (in Latin) (2nd ed.). Stockholmiae: Sumtu & Literis Direct. Laurentii Salvii. p. 39.
  5. ^ Mayr, Ernst; Cottrell, G. William, eds. (1979). Check-List of Birds of the World. Vol. 1 (2nd ed.). Cambridge, Massachusetts: Museum of Comparative Zoology. p. 486.
  6. ^ Boie, Friedrich (1822). Tagebuch gehalten auf einer Reise durch Norwegen im Jahre 1817 (in German). Schleswig. pp. 308, 351.
  7. Rasmussen, Pamela, eds. (2020). "Screamers, ducks, geese, swans"
    . IOC World Bird List Version 10.1. International Ornithologists' Union. Retrieved 23 March 2020.
  8. ISBN 978-1-4081-2501-4
    .
  9. ISBN 978-0691162669
    .
  10. S2CID 250043960
  11. ^ Banks, R.C. (1986). "Subspecies of the Greater Scaup and their names" (PDF). Wilson Bulletin. 98 (3): 433–444.
  12. ISBN 978-0-19-861271-1
    .
  13. JSTOR 4088937
    .
  14. ^ a b c d e "Greater Scaup". Bird Web. Seattle Audubon Society. Retrieved 26 October 2011.
  15. ^ a b "Greater Scaup". Ducks Unlimited. Retrieved 1 November 2011.
  16. ^ "Greater Scaup". enature.com. Archived from the original on 12 February 2012. Retrieved 11 December 2011.
  17. ^ a b c "Greater Scaup Aythya marila". Bird Life International. Retrieved 9 March 2015.
  18. ^ a b c d e "Greater Scaup". Avibirds European birdguide online. Retrieved 8 November 2011.
  19. ^ a b "Greater Scaup". The Birds of North America. Cornell Lab of Ornithology. Retrieved 2 January 2011.
  20. ISBN 978-91-46-17633-6
    .
  21. ISBN 978-91-34-51940-4
    .
  22. ^ a b Mayntz, Melissa. "Greater Scaup". About.com. Archived from the original on 10 March 2010. Retrieved 20 August 2011.
  23. ^ a b c d "Greater Scaup". Utah Department of Natural Resources. Retrieved 8 November 2011.
  24. ^ "Greater Scaup". All About Birds. Cornell Lab of Ornithology. Retrieved 18 December 2011.
  25. ^ "Greater Scaup". National Audubon Society, Inc. Archived from the original on 25 April 2012. Retrieved 27 November 2011.
  26. ^ "Greater Scaup". Ohio Department of Natural Resources. Retrieved 9 March 2015.
  27. doi:10.14430/arctic801. Archived from the original
    on 2012-04-25.
  28. ^ Longley, William H. (1948). "Greater scaup eating frogs" (PDF). The Auk. 66 (2): 200.
  29. ^ "Greater Scaup". Audubon. National Audubon Society. Archived from the original on 11 November 2010. Retrieved 26 October 2011.
  30. ^ "Greater Scaup". United States Fauna. Archived from the original on 21 October 2013. Retrieved 2 November 2011.
  31. ^ "Greater Scaup". National Biological Information Infrastructure. Archived from the original on 9 December 2011. Retrieved 8 November 2011.
  32. doi:10.1016/0048-9697(87)90173-2
    .
  33. ^ "Waterfowl Hunting Management in North America". Scaup Population Estimates. U.S. Fish and Wildlife Service in collaboration with flyway and state waterfowl managers. 29 June 2010. Retrieved 4 November 2011.
  34. ^ "Banding and Marking Programs". U.S. Fish and Wildlife Service. Retrieved 28 November 2011.
  35. ^ a b "European Union Management Plan" (PDF). EU. European Union. Retrieved 2 November 2011.
  36. ^ "Greater Scaup". Discover the Outdoors. Retrieved 19 November 2011.

Further reading

External links

Wikimedia Commons has media related to Aythya marila.
Wikispecies has information related to Aythya marila.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Greater_scaup&oldid=1206998782"