Common Goldeneye (Bucephala clangula) – Wildlife of Japan

Introduction

The Common Goldeneye (Bucephala clangula), known in Japan as the Hoojirogamo, is a striking diving duck notable for its bold male plumage and winter presence in Japanese waters. Although its main breeding grounds are far to the north, this species brings seasonal interest to coastal and lake habitats in Japan.

Appearance

The male measures about 45–47 cm, with a glossy green-black head and a distinct round white cheek patch between the eye and bill. The back and wings are black, while the underparts are pure white, creating a sharp contrast. The eyes are bright yellow.
The female, smaller and more subdued, has a brown head and greyish body without the white cheek patch. The base of her bill is tinged with orange.

Habitat & Distribution

The Common Goldeneye breeds across the northern forests of Eurasia and North America, nesting in tree cavities near lakes and rivers. In Japan, however, it is a winter visitor.
During the cold months, it appears in coastal bays, estuaries, harbors, and large lakes, especially in Hokkaido and northern Honshu. In southern regions, sightings are rare.

Where to See in Japan

Best observed between December and March, especially in northern Japan. Look for them in calm coastal waters or large unfrozen lakes. Good viewing spots include Lake Tōya, Lake Kussharo, and the coasts of Hokkaido.

Behavior

The Common Goldeneye is an active diving duck. It frequently dives beneath the surface to catch aquatic prey and often surfaces with a shellfish or small fish in its bill.
In winter, they gather in small groups and are seen diving repeatedly in rhythm. Their take-off from the water is distinctive — they need to run across the surface before becoming airborne.

Diet

This species feeds mainly on aquatic invertebrates such as crustaceans, molluscs, and aquatic insects, but also takes small fish and plant material. It hunts by diving to the bottom and foraging along the substrate.

Reproduction

The Common Goldeneye does not breed in Japan. In northern breeding grounds, females nest in tree cavities, laying 7–11 eggs which hatch after about 27–30 days. The ducklings leave the nest soon after hatching and are led to the water by the female.

Conservation

Globally, the Common Goldeneye is listed as Least Concern (LC) by the IUCN, but in Japan its wintering population is small. Kyoto Prefecture, for example, designates it as a Near Threatened species.
Habitat disturbance, pollution, and reduced food availability are possible local threats. Protecting clean coastal bays and maintaining undisturbed wintering areas are important conservation measures.

Author’s Impression

On a snowy winter day, I visited a frozen lake to watch waterbirds. Among groups of Eurasian Coots and Wigeons, I noticed one bird that looked completely different — it was a Common Goldeneye.
Its bold black-and-white plumage stood out against the grey water and falling snow. Watching it dive repeatedly among the other ducks was a quiet but memorable scene, a perfect symbol of Japan’s winter wildlife.