Common goldeneye

thumb|Bucephala clangula pair

thumb|Female goldeneye with chicks

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. The genus name is derived from the Ancient Greek ("bullheaded", from , "bull" and , "head"), a reference to the bulbous head shape of the bufflehead. The species name is derived from the Latin ("to resound").

Common goldeneyes are aggressive and territorial ducks, and have elaborate courtship displays. Linnaeus specified the type location as Europe but in 1761 restricted this to Sweden. 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. The genus name is from Ancient Greek meaning "bullheaded" or "large-headed". The specific epithet is from Latin meaning "to resound".

Two subspecies are recognised: 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.

Distribution and habitat

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. though they will readily use nest boxes as well.

Behaviour

Breeding

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. Average egg size is a breadth of , a length of and a weight of . 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. Goldeneye young have been known to be competitively killed by other goldeneye mothers, common loons and red-necked grebes. 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.

Predators

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).

Conservation

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. 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.

thumb|upright|Eggs, Collection [[Museum Wiesbaden]]

Gallery

File:Bucephala clangula male.jpg|Male portrait

File:Bucephala clangula female.jpg|Female portrait

File:Common Goldeneye with nictitating membrane.JPG|Just after a dive, showing clear nictitating membrane

File:Goldeneyes in flight.jpg|In flight over Rideau River, Ottawa, Ontario

File:Common Goldeneye with Northern Crayfish on Seedskadee NWR (24188167270).jpg|With a northern crayfish (Orconectes virilis)

File:Bucephala clangula 18042024 Kaijonlahti, Finland 02.jpg|Bucephala clangula in icy Kaijonlahti in Kuivasjärvi, Oulu, Finland

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References

External links

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) at ornithos.de