Oscar Dewhurst / Mandarin duck (Aix galericulata) drake swimming on pond, backlit by rising sun and bokeh effect, Richmond Park, London, UK. February.

Jordi Chias / Wandering albatross (Diomedea exulans) flying on the open ocean, Drake passage, Antarctic Peninsula, Antarctica.

Marie Read / Wood Ducks (Aix sponsa), females behave aggressively toward a male (second from right) that is trying to join them on a floating log, autumn, New York, USA, October.

Russell Cooper / Mandarin duck drake (Aix galericulata) from behind flapping its wings. Southwest London, UK. February.

Russell Cooper / Mandarin duck drake (Aix galericulata) on the water, showing orange 'sail' feathers which are used when displaying, Southwest London, UK, March.

Ross Hoddinott / Mallard duck (Anas platyrhynchos) drake swimming through reflection of house, Bude canal, Cornwall, UK. April 2015.

David Tipling / 2020VISION / Garganey duck (Anas querquedula) drake calling, Cley, Norfolk, UK, May

Ben Hall / Eider (Somateria mollissima) male swimming, Northumberland, UK

Ben Hall / Goldeneye duck (Bucephala clangula) drake performing courtship display, Lancashire, UK February

Nick Upton / Mallard (Anas platyrhynchos) drake sliding on fresh snow after landing on frozen lake surface, Wiltshire, UK, February

Chris Gomersall / 2020VISION / Common teal (Anas crecca) drake feeding on mudflats, The Wash, Norfolk, England, UK, March

Brent Stephenson / Flock of Cape petrels (Daption capense capense) in flight against the sea. Against the sun. South Shetland Islands, Antarctica, January.

Brent Stephenson / Waves crashing on a massive iceberg. Drake Passage, near the South Shetland Islands, Antarctica, January.

Brent Stephenson / A rough and windy day in the Drake Passage with Force 9+ beaufort scale conditions. Drake Passage, South Atlantic, January.

Brent Stephenson / Huge iceberg with streaked sky under expansive open sky. Drake Passage, near the South Shetland Islands, Antarctica, December.

Brent Stephenson / Light-mantled Sooty Albatross (Phoebetria palpebrata) close up in flight at eye level, portrait. Drake Passage, South Atlantic, December.

Florian Möllers / Mandarin duck (Aix galericulata) rear view of drake in breeding plumage, displaying, Berlin, Germany.

Nick Upton / 2020VISION / Northern shoveler drake (Anas clypeata) reflected in calm water as it swims among reeds and rushes in flooded marshland on a sunny winter afternoon. Greylake RSPB reserve, Somerset Levels, UK, January

Steve Knell / Tufted duck (Aythya fuligula) drake on water with Midges (Chironomidae) Iceland. June

Paul Hobson / Mallard drake (Anas platyrhynchos) portrait of male on water, with autumn colours reflecting. Lancashire, England, UK. November.

Paul Hobson / Mallard drake (Anas platyrhynchos) male on water, with autumn colours reflecting. Lancashire, England, UK. November.

Floris van Breugel / Twilight descends on photographer's mountain camp with light inside tent, in Oregons highest mountain forest on Drake Peak at 8,500 feet. Oregon, USA, January 2010.

Wild Wonders of Europe / Geslin / Mallard (Anas platyrhynchos) male in flight in the Vatican garden, Rome, Italy, March 2010

Colin Varndell / Drake Tufted duck (Aythya fuligula) in breeding plumage, Gloucestershire, UK, February

Andy Rouse / Rays of light shining through storm clouds over Drake Passage, Antarctica, February 2006

Kim Taylor / Eider (Somateria mollissima) drake, captive, Sussex, England

Mark Carwardine / Mallard (Anas platyrhynchos) drake flying, Bosque del Apache National Wildlife Refuge, New Mexico, USA

Markus Varesvuo / Mallard duck (Anas platyrhynchos) drake amongst icy reeds, Helsinki, Finland, February

Graham Eaton / Mallard (Anas platyrhynchos) drake on lake with autumn reflections, Lancashire, UK, November

Kim Taylor / Anglers / Green Drake Mayfly (Ephemera danica) males flying at sunset. digital composite, Surrey, UK

Graham Eaton / Male Mallard {Anas platyrhynchos} swimming on water, split level view, Wales, UK, 2006

Chris Gomersall / Black-browed albatross (Thalassarche melanophrys) in flight over ocean, Drake Passage, Southern Ocean, Antarctica.

Chris Gomersall / Black-browed albatross (Thalassarche melanophrys) in flight over ocean, Drake Passage, Southern Ocean, Antarctica.

Pete Cairns / Mallard drake portrait standing on ice {Anas platyrhynchos} Highlands, Scotland, UK

Donald M. Jones / Mallard (Anas platyrhynchos) drake flying, Montana

Thomas Hinsche/ BIA / Common Goldeneye (Bucephala clangula) male flapping, Saxony-Anhalt, Germany

Donald M. Jones / Wood Duck (Aix sponsa) drake flying, central Montana

Donald M. Jones / Wood Duck (Aix sponsa) drake stretching wings, central Montana

Donald M. Jones / Northern Pintail (Anas acuta) drake flying, central Montana

Donald M. Jones / Mallard (Anas platyrhynchos) drake flying, central Montana

Donald M. Jones / American Wigeon (Anas americana) drake, western Montana

Tim Zurowski / Wood Duck (Aix sponsa) male calling, British Columbia, Canada

Alan Murphy / Wood Duck (Aix sponsa) male, Texas

Alan Murphy / Green-winged Teal (Anas carolinensis) male calling, Texas

Alan Murphy / Green-winged Teal (Anas carolinensis) male, Texas

Alan Murphy / Ruddy Duck (Oxyura jamaicensis) male in courtship display, British Columbia, Canada

Rob Drummond / Chestnut Teal (Anas castanea) male, Victoria, Australia

Hans Glader / Mallard (Anas platyrhynchos) male flying, Carinthia, Austria