Laurent Geslin / Red breasted merganser (Mergus serrator) male on Lake Geneva, near Geneva, Switzerland

Laurent Geslin / Red breasted merganser (Mergus serrator) male grooming, on Lake Geneva, near Geneva, Switzerland

Marie Read / Red-breasted Mergansers (Mergus serrator) male in foreground performing courtship display to female in background (left), Aurora, New York, USA, April.

John Chan / Red-breasted merganser (Mergus serrator) preening on a sandbar, with Western sandpipers (Calidris mauri) feeding in the foreground, Bolsa Chica Ecological Reserve, California, USA, April.

Roger Powell / Red-breasted merganser (Mergus serrator) male courtship display to a female standing on the edge of the ice, with another male watching. Kolvik, Porsanger fjord, Finnmark, Norway, June.

Sandra Bartocha / Red-breasted mergansers (Mergus serrator) on Tundra Lake Nordkinn-Peninsula, Norway

Martin Grimm/ BIA / Red-breasted Merganser (Mergus serrator) male taking flight, Mecklenburg-Vorpommern, Germany

Raymond Besant / 2020VISION / Red-breasted merganser (Mergus serrator) feeding in a river, Coigach / Assynt Scottish Wildlife Trust Reserve, Sutherland, Highlands, Scotland, UK, June.

Robin Chittenden / Red-breasted Merganser (Mergus serrator) male and females flying over the sea, Norfolk, UK, November.

Cyril Ruoso / Red-breasted merganser (Mergus serrator) on water, Skjaervaer Island, Vega archipelago, Norway June

Cyril Ruoso / Red-breasted merganser (Mergus serrator) on water, Lanan Island, Vega archipelago, Norway June

Cyril Ruoso / Red-breasted merganser (Mergus serrator) on water, Lanan Island, Vega archipelago, Norway June