Common GoldeneyeBucephala clangulaWhere and when to see them

The Common Goldeneye is a medium-sized diving duck, registered here as Bucephala clangula. An adult male has a striking black-and-white body pattern, a dark head with a greenish sheen and a circular white patch in front of the yellow eye. Females are smaller and greyer, with a chocolate-brown head. Both sexes can show a large white area in the inner wing during flight. Goldeneyes obtain much of their food underwater rather than simply picking items from the surface. Their use of open water makes a telescope valuable when birds remain far from shore. The registered Rhine location is Strasbourg’s Rohrschollen island, specifically the Vieux Rhin and Grand Canal setting. LPO Alsace names goldeneyes in its winter waterbird section there, providing direct local seasonal context without establishing an exact monthly calendar or a guaranteed cruise-deck encounter.

Size

42–50 cm (16.5–19.7 in) body length

Weight

650–1,200 g (22.9–42.3 oz), according to RSPB

Lifespan

Not independently verified in the retrieved evidence

Status

See sourced assessment

A feeding goldeneye repeatedly disappears beneath the surface and reappears some distance away. Following one bird patiently is more informative than switching between every duck in a scattered flock. Diving creates natural gaps in visibility, so a temporarily empty patch of water does not mean the birds have departed. Individuals may rest between feeding bouts, preen on the surface or move with other diving ducks. Courtship includes conspicuous head movements, though display behaviour should not be treated as proof of local nesting. Goldeneyes are cavity-nesting ducks, and the RSPB notes their use of specially designed tree-mounted nest boxes in Scotland. That example explains a species behaviour, not a nesting claim for Rohrschollen. From the Rhine shore, watch the sequence of diving, resurfacing and resting while maintaining enough distance that the birds do not swim away or take flight in response.

• Goldeneye is a diving duck.
• Adult males have a circular white facial patch.
• Females have chocolate-brown heads.
• Both sexes show substantial white in the inner wing.
• RSPB gives a body length of 42–50 cm (17–20 in).
• RSPB gives a wingspan of 65–80 cm (26–31 in).
• Its diet includes mussels and insect larvae.
• Goldeneyes can nest in tree cavities and suitable nest boxes.
• LPO Alsace explicitly lists the species at Rohrschollen in winter.

Winter is directly supported for Common Goldeneye at Rohrschollen: LPO Alsace places garrots à œil d’or in its section headed En hiver and names the Grand Canal d’Alsace and Vieux Rhin as viewing waters. That is useful local species-specific seasonal evidence. It does not, however, define which numbered months the author intended, so the monthly array remains empty rather than translating winter automatically into December through February or a longer migration window. The opportunity also depends on water conditions, disturbance and whether ducks are close enough for a shore view. British winter influx information and Scottish nesting history should not be used to expand the Strasbourg calendar. For a visit, prioritise current local waterbird reports and accessible viewpoints during the locally described winter period. A telescope and time for repeated scans are more useful than assuming every visible diving duck is a goldeneye.

Goldeneyes use aquatic habitats that allow underwater feeding, including lakes, rivers and coastal waters. Breeding habitat and winter feeding habitat need not be identical: a duck that nests in a tree cavity can spend the nonbreeding period on much more open water. At Rohrschollen, the relevant local account identifies both the Grand Canal d’Alsace and the Vieux Rhin as places for watching winter waterbirds, explicitly including goldeneyes. This is more precise than a general statement that the species occurs somewhere along the Rhine. Shore access and sightlines determine whether the birds can actually be viewed safely. Use established viewpoints and do not approach waterside cover or infrastructure simply to shorten the viewing distance. The registered association remains the Strasbourg island and adjacent named waters; it should not be expanded to the entire Upper Rhine, other islands or unrelated winter duck concentrations without separate evidence.

The RSPB lists mussels, insect larvae, small fish and plants among Common Goldeneye foods. The species is therefore an underwater forager with a varied diet rather than an exclusively fish-eating duck. Repeated dives allow it to search below the surface for prey and other food unavailable to birds feeding only in the uppermost water layer. The exact mixture depends on the waterbody and the resources available there. A duck surfacing with an item may provide a useful glimpse, but most feeding cannot be identified from shore. Do not infer a specific Rhine diet simply from the general species food list. Watching dive location, duration and the spacing of birds can still reveal how they use a feeding area. Avoid feeding waterbirds or throwing material into the water to draw them closer. A quiet telescope view preserves natural behaviour and avoids creating an artificial concentration beside visitors.

Common name

Common Goldeneye

Scientific name

Bucephala clangula

Animal group

Birds

Size

42–50 cm (16.5–19.7 in) body length

Weight

650–1,200 g (22.9–42.3 oz), according to RSPB

Lifespan

Not independently verified in the retrieved evidence

Status

RSPB UK Birds of Conservation Concern: Red. This does not establish the global or French category.

Identification

An adult male goldeneye is strongly patterned: black and white overall, with a dark greenish head, yellow eye and a round white patch between the eye and bill. The female has a chocolate-brown head and a grey, mottled body, and is smaller than the male. A large white inner-wing area is useful in flight for both sexes. Compare the entire head shape and facial pattern rather than relying on a yellow eye, which is not unique to this species. Tufted Duck and other diving ducks can occur in the same waterbird assemblage and may look similarly dark and white at a distance. Light can conceal the green sheen or make it appear black, so iridescence is supporting rather than essential evidence. Follow a candidate through several surfacings and, if possible, a wing stretch before deciding. Do not assign female or immature birds solely by association with an obvious male.