Common goldeneye
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The common goldeneye or simply goldeneye (Bucephala clangula) is a medium-sized sea duck of the genus Bucephala, the goldeneyes. Its closest relative is the similar Barrow's goldeneye.<ref name=":0">Template:Cite journal</ref> The genus name is derived from the Ancient Greek boukephalos ("bullheaded", from bous, "bull " and kephale, "head"), a reference to the bulbous head shape of the bufflehead. The species name is derived from the Latin clangere ("to resound").
Common goldeneyes are aggressive and territorial ducks, and have elaborate courtship displays.<ref name=":0" />
TaxonomyEdit
The common goldeneye was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae under the binomial name Anas clangula.<ref>Template:Cite book</ref> Linnaeus specified the type location as Europe but in 1761 restricted this to Sweden.<ref>Template:Cite book</ref><ref>Template:Cite book</ref> The common goldeneye is now one of three species placed in the genus Bucephala that was introduced in 1858 by the American naturalist Spencer Baird.<ref name=ioc>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The genus name is from Ancient Greek oukephalos meaning "bullheaded" or "large-headed". The specific epithet is from Latin "clangere" meaning "to resound".<ref>Template:Cite book</ref>
Two subspecies are recognised:<ref name=ioc/>
- B. c. clangula (Linnaeus, 1758) – subarctic from Scotland and Scandinavia to Sakhalin and Kamchatka Peninsula (southeast Russia), in south through north Kazakhstan, north Mongolia and Heilongjiang (northeast China)
- B. c. americana (Bonaparte, 1838) – subarctic from west Alaskan mainland to Labrador and New Brunswick, south through northern USA
DescriptionEdit
Adult males range from Template:Convert and weigh approximately Template:Convert, while females range from Template:Convert and weigh approximately Template:Convert.<ref name=":0" /> The common goldeneye has a wingspan of Template:Convert.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The species is named for its golden-yellow eyes. Adult males have a dark head with a greenish gloss and a circular white patch below the eye, a dark back and a white neck and belly. Adult females have a brown head and a mostly grey body. Their legs and feet are orange-yellow.
The subspecies B. c. americana has a longer and thicker bill than the nominate B. c. clangula.<ref name=Reeber>Template:Cite book</ref>
Distribution and habitatEdit
Their breeding habitat is the taiga. They are found in the lakes and rivers of boreal forests across Canada and the northern United States, Scotland, Scandinavia, the Baltic States, and northern Russia. They are migratory and most winter in protected coastal waters or open inland waters at more temperate latitudes.<ref name=":0" /> Naturally, they nest in cavities in large trees, where they return year after year,<ref>Template:Cite journal</ref> though they will readily use nest boxes as well.<ref>Template:Cite journal</ref>
BehaviourEdit
BreedingEdit
Natural tree cavities chosen for nest sites include those made by broken limbs and those made by large woodpeckers, specifically pileated woodpeckers or black woodpeckers.<ref>Template:Cite book</ref> Average egg size is a breadth of Template:Convert, a length of Template:Convert and a weight of Template:Convert.<ref name=":0" /> The incubation period ranges from 28 to 32 days. The female does all the incubating and is abandoned by the male about 1 to 2 weeks into incubation. The young remain in the nest for about 24–36 hours. Brood parasitism is quite common with other common goldeneyes,<ref>Template:Cite journal</ref> and occurs less frequently with other duck species. The broods commonly start to mix with other females' broods as they become more independent or are abandoned by their mothers.<ref>Template:Cite journal</ref> Goldeneye young have been known to be competitively killed by other goldeneye mothers, common loons and red-necked grebes.<ref name=":0" /> The young are capable of flight at 55–65 days of age.
Food and feedingEdit
Common goldeneyes are diving birds that forage under water. Year-round, about 32% of their prey is crustaceans, 28% is aquatic insects and 10% is molluscs.<ref>Template:Cite report</ref> Insects are the predominant prey while nesting and crustaceans are the predominant prey during migration and winter. Locally, fish eggs and aquatic plants can be important foods.
PredatorsEdit
They themselves may fall prey to various hawks, owls and eagles, while females and their broods have been preyed upon by bears (Ursus spp.), various weasels (Mustela spp.), mink (Mustela vison), raccoons (Procyon lotor) and even northern flickers (Colaptes auratus) and American red squirrels (Tamiasciurus hudsonicus).
ConservationEdit
The common goldeneye is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies. Around 188,300 common goldeneyes were killed annually by duck hunters in North America during the 1970s, representing slightly less than 4% of the total waterfowl killed in Canada during that period, and less than 1% of the total waterfowl killed in the US.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Both the breeding and winter habitats of these birds have been degraded by clearance and pollution. However, the common goldeneye in North America is known to derive short-term benefits from lake acidification.<ref>Template:Cite journal</ref>
GalleryEdit
- Bucephala clangula male.jpg
Male portrait
- Bucephala clangula female.jpg
Female portrait
- Common Goldeneye with nictitating membrane.JPG
Just after a dive - showing clear nictitating membrane
- Goldeneyes in flight.jpg
In flight over Rideau River, Ottawa, Ontario
- Common Goldeneye with Northern Crayfish on Seedskadee NWR (24188167270).jpg
With a northern crayfish (Orconectes virilis)
- Bucephala clangula 18042024 Kaijonlahti, Finland 02.jpg
Bucephala clangula in icy Kaijonlahti in Kuivasjärvi, Oulu, Finland.
ReferencesEdit
External linksEdit
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- Common Goldeneye Species Account – Cornell Lab of Ornithology
- Common Goldeneye - Bucephala clangula - USGS Patuxent Bird Identification InfoCenter
- eNature.com: Common Goldeneye
- Common Goldeneye wildlife photos and voice at nature-photos.org
- Feathers of Common Goldeneye (Bucephala clangula) Template:Webarchive at ornithos.de
- Template:VIREO
- Template:IUCN Map
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