Barrow's goldeneye

Bucephala islandica

IJslandse brilduiker / Spatelente / Garrot d'Islande

Barrow's goldeneye is a medium-sized sea duck of the genus Bucephala, the goldeneyes. This bird was named after Sir John Barrow. Adults are similar in appearance to the common goldeneye.

Their breeding habitat is wooded lakes and ponds primarily in northwestern North America but also in scattered locations in eastern Canada and Iceland. Females return to the same breeding sites year after year and also tend to use the same nesting sites. the males stay with their mate through the winter and defend their territory during the breeding season, then leave for molting site. Mating pairs often staying intact even though the make and female are apart for long periods of time over the summer during molting times. The pair then reunites at wintering areas.

They are migratory and most winter in protected coastal waters or open inland waters. In winter, they migrate to the coast. Barrow's goldeneye, along with many other species of sea ducks, rely on urbanized, coastal estuaries as important places on their migration patterns. These estuaries provide excellent wintering and stopping places during the ducks migration. It is an extremely rare vagrant to western Europe and to southern North America.

These diving birds forage underwater. They eat aquatic insects, crustaceans and pond vegetation. The main staples of the bird's diet are Gammarus oceanicus and Calliopus laeviusculus which are both marine crustaceans. A large part of their diet also consists of mussels and gastropods.

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern (IUCN, 2012).

The major breeding range of Barrow's Goldeneye is along the western coast of the USA from southern Alaska to northern California. Breeding colonies are also found in Labrador (Canada), south-west Greenland (to Denmark) and Iceland. Some populations (e.g. Iceland) are sedentary, whereas others undertake longer trips to winter along the Pacific coast of Alaska and Canada, and the north-eastern coast of North America (del Hoyo et al. 1992).

This species breeds on freshwater lakes, pools and rivers in open or wooded country. It can be seen nesting as high as 3000 m in the Rocky Mountains (USA). After breeding individuals winter on larger, unfrozen lakes, brackish coastal lagoons or on the coast. Summers foods include insects and their larvae and plant material, whereas winter diet consists mainly of molluscs and crustaceans (del Hoyo et al. 1992).

Above: Barrow's goldeneyes, adult pair, drake left

Above: adult drake Barrow's goldeneye

Above: adult pair Barrow's goldeneye, drake in foreground

Above: adult pair Barrow's goldeneye, drake in foreground

Above: adult pair Barrow's goldeneye, drake left

Above: adult drake Barrow's goldeneye

Above: an adult pair of Barrow's goldeneye