Long-tailed duck (Clangula hyemalis)
The long-tailed duck (Clangula hyemalis) is a small diving duck with a short bill and small head. It has a circumpolar distribution and nests both in mountainous regions and in lowlands, often far from the coast. It is thought to be migratory, but its movements are very poorly documented. The long-tailed duck breeds mainly in the western parts of Spitsbergen and on Bjørnøya within Svalbard.
The long-tailed duck is a small diving duck with a short bill and small head. It is a sexually dimorphic species in which the male is larger and more brightly coloured than the female. Males are 53 cm long while females are approximately 40 cm long. Adult weights vary between 600 and 900 g. The male has central tail-feathers that are up to 13 cm long, which gives rise to the common name for this duck. The male (in nesting plumage) has a dark brown back, white belly and brown-black neck and head with a large white patch around the eye. In winter plumage it has a white head, neck, belly and parts of the back, while the breast and the wings are brown. In spring and autumn it has an intermediate transitional plumage. The female in nesting plumage has a dark brown back and white under-parts and brown-black head with a large white patch around the eye and down the side of the neck. The colour markings on the neck and head vary through the year. The male emits characteristic, melodic notes while the female makes fainter barking noises.
The long-tailed duck has a circumpolar distribution and breeds throughout Alaska, northern Canada, Greenland, Iceland, Svalbard, Fennoscandia, the Kola Peninsula and Siberia. The species nests both in mountainous regions and in lowlands, often far from the coast. It is thought to be migratory, but its movements are very poorly documented. The long-tailed duck breeds mainly in the western parts of Spitsbergen and on Bjørnøya within Svalbard. Solitary pairs breed on small islands and along the coast of Spitsbergen, close to freshwater ponds. Observations from the mid 1990s suggest that at least some individuals from the Svalbard population winter in ice-free waters off the west coast of Svalbard, mainly along Nordenskiöldkysten and Prins Karls Forland. Long-tailed ducks can be seen along the ice-edge early in spring. Important wintering areas are located along the coast of northern Norway and in the Baltic.
The long-tailed duck breeds on the tundra, usually near freshwater ponds and lakes. Several pairs may nest close together though the species is not regarded as being a colonial breeder. The nests are often placed in colonies of arctic terns, which affords them protection against predators such as the artic fox, glaucous gull and arctic skua.
Incubating female long-tailed ducks remain on the nest until the last possible moment when an intruder approaches, similar to common eider females. Studies performed in Ny-Ålesund showed that incubating females left the nest three or four times during each 24 hour period. The female usually flew out to sea, but was back after only three or four minutes. The eggs are covered with down when left, but are still vulnerable to predators.
The males are very territorial and occupy the same area every year. The territory usually includes a freshwater pool where intense courtship behaviour occurs.
Outside the breeding season long-tailed ducks stay mainly in coastal waters. They show considerable variation in habitat use and dive to various depths.
Their diet consists mainly of invertebrates, but they also feed on some plant matter. In Svalbard long-tail ducks eat mussels, crustaceans and insect larvae.
Life history and reproduction
The long-tailed duck starts breeding as soon as the breeding area is free of ice in late June.
The nest is lined with dark-coloured down that has white speckles; the nest itself is a shallow depression directly on the tundra. In Svalbard there is little vegetation to provide cover, but the brown plumage of the incubating females makes them very difficult to detect.
The five to nine pale grey-green eggs are laid in the latter half of June. The female incubates the eggs for four weeks. The males leave the females early in the incubation period and go out to the coast where they moult either singly or in small flocks.
The young follow the female to a nearest freshwater pond shortly after hatching. They stay here for some time, before moving out to sea. The young are fledged after five to six weeks and become independent of the adults. The females moult somewhat later than the males. The highest age recorded in Norway (including Svalbard) is eight years.
Management status and monitoring
The size of theSvalbardbreeding population is not known, and there is no monitoring of population trends. The European breeding population is estimated to be 690,000 pairs, and is thought to be stable. The segment of the breeding population that winters off the west coast of Spitsbergen is vulnerable to oil spills and disturbance if these occur because they are energetically challenged in winter, and many birds gather together in a restricted area.
MOSJ indicators (Environmental Monitoring of Svalbard and Jan Mayen):
Awaiting results from MOSJ…