Common Goldeneye

The common goldeneye, Bucephala clangula, is a medium-sized sea duck known for its striking golden-yellow eyes. Males exhibit a dark head with a greenish sheen and a distinctive white patch below the eye, contrasting with their dark back and white underparts. Females are characterized by a brown head and a predominantly grey body. Both sexes have orange-yellow legs and feet, with adult males typically measuring 45–51 cm in length and weighing around 1,000 g, while females are slightly smaller, ranging from 40–50 cm and weighing approximately 800 g. The species boasts a wingspan of 77–83 cm.

Identification Tips

To identify the common goldeneye, look for the male's glossy greenish-black head and the white spot near the bill. Females can be recognized by their chocolate-brown head and grey body. In both sexes, the vibrant golden eyes are a distinguishing feature. The species exhibits sexual dimorphism, with males being larger and more vividly colored than females.

Habitat

The common goldeneye favors the taiga's lakes and rivers, thriving in the boreal forests that stretch across Canada, the northern United States, parts of Scotland, Scandinavia, the Baltic States, and northern Russia.

Distribution

These ducks are migratory, breeding in northern regions and wintering along protected coastal waters or open inland waters at more temperate latitudes.

Behaviour

The common goldeneye is known for its aggressive and territorial nature, particularly during the breeding season when they perform elaborate courtship displays. They are cavity nesters, often returning to the same natural tree cavities year after year, though they will also adapt to nest boxes.

Song & Calls

The species name, clangula, is derived from the Latin for "to resound," hinting at the notable calls of this species.

Breeding

Goldeneyes lay their eggs in tree cavities, with average egg dimensions of 42.6–44.0 mm by 58.1–60.6 mm and a weight of 61.2–66.6 g. The incubation period lasts 28 to 32 days, with the female undertaking all incubation duties. After hatching, the young remain in the nest for about 24–36 hours and are capable of flight at 55–65 days of age. Brood parasitism is common within the species, and mixed broods are not unusual.

Similar Species

The common goldeneye's closest relative is the Barrow's goldeneye, which can be differentiated by subtle variations in head shape and plumage details.

Diet and Feeding

As diving ducks, common goldeneyes forage underwater, feeding on crustaceans, aquatic insects, molluscs, fish eggs, and occasionally aquatic plants. Their diet varies seasonally, with insects being more prevalent during nesting and crustaceans during migration and winter.

Conservation status

The common goldeneye is classified as Least Concern by the IUCN. While they face threats from habitat degradation and pollution, they have shown some resilience, such as deriving short-term benefits from lake acidification in North America. Conservation efforts under the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) apply to this species.