Pete Oxford / Pair of Black swans {Cygnus atratus} Tasmania, Australia

SIMON KING / Mute swan female at nest with newly hatched chick (Cygnus olor) England, UK

Chris Packham / Bewicks swans in winter. (Cygnus columbianus bewickii) England Hampshire, UK

David Kjaer / Mute swan bathing {Cygnus olor} Gloucestershire, UK, Europe

WILLIAM OSBORN / Bewicks swan standing on ice portrait (Cygnus columbianus bewickii) UK

John Cancalosi / Mute swan sitting on ice portrait (Cygnus olor) England

Steve Knell / Mute swan pair with chicks on water {Cygnus olor} UK

David Pike / Whooper swan on water {Cygnus cygnus} Akan ko, Japan

David Kjaer / Male Mute swan swimming with feather's puffed up {Cygnus olor} Gloucestershire, UK

Colin Seddon / Whooper swan portrait {Cygnus cygnus} Scotland, UK

Geoff Simpson / Bewick swan on water {Cygnus columbianus bewickii} Washington WWT, Co Durham, UK

John Downer / Mute swans flying {Cygnus olor} Slimbridge, Glos, UK

Asgeir Helgestad / Whooper swans in temperature of -30 degrees C Numedalslagen river, Norway

Asgeir Helgestad / Whooper swan pair with two cygnets {Cygnus cygnus} Norway

TJ Rich / Very young Mute swan cygnet {Cygnus olor} Dorset, England, UK, Europe

Tom Vezo / Trumpeter swans, Denali NP, Alaska, USA

GRANT MCDOWELL / Imprinted Whooper swan in flight, England

Espen Bergersen / Whooper swan (Cygnus cygnus). Iceland

Oscar Dewhurst / Trumpeter swan (Cygnus buccinator) pair on bank. Grand Teton National Park, Wyoming, USA. September.

Roger Powell / Mute swan pair (Cygnus olor) mating. Potterick Carr, Doncaster, Yorkshire, UK, March.

Roger Powell / Mute swan pair (Cygnus olor) engaged in courtship. Potterick Carr, Doncaster, Yorkshire, UK, March.

Roger Powell / Mute swan pair (Cygnus olor) engaged in courtship. Potterick Carr, Doncaster, Yorkshire, UK, March.

Loic Poidevin / Black Swans (Cygnus atratus) foraging in water, Marsh of Ile d'Olonne, Vendee, France. July.

Nick Garbutt / Black-necked swan (Cygnus melancoryphus) pair in courtship on upland lake. Torres del Paine National Park, Patagonia, Chile. November 2018.

Oscar Dewhurst / Mute swan (Cygnus olor) two immature birds taking off from water, on misty morning. Richmond Park, London, England, UK. February.

Oscar Dewhurst / Mute swan (Cygnus olor) cygnet resting. Richmond Park, London, England, UK. April.

Oscar Dewhurst / Mute swan (Cygnus olor) cygnet swimming, cocking head. Barnes, London, England, UK. April.

Loic Poidevin / Whooper swan (Cygnus cygnus) pair swimming, reflected in water. Finland. May,

Bernard Castelein / Mute Swan (Cygnus olor) bathing, Paris, France. November

Mike Read / Pools and grazing land. Catcott Lows Nature Reserve, near Edington, Somerset Levels, England, UK. October 2018

Mike Read / Mute swan (Cygnus olor), group at sunrise. King's Sedgemoor Drain at sunrise near Greylake, Somerset Levels, England, UK, October 2018

Andy Rouse / Mute swan (Cygnus olor) stretching wings on water. In morning light, Wales, UK. February.

Andy Rouse / Mute swan (Cygnus olor) stretching wings on water. In morning light, Wales, UK. February.

Robin Chittenden / Whooper swan (Cygnus cygnus) Norfolk, England, UK January.

Robin Chittenden / Whooper swan (Cygnus cygnus) Norfolk, England, UK, January.

Robin Chittenden / Whooper Swan (Cygnus cygnus) Norfolk, England, UK, January.

Robin Chittenden / Whooper swan (Cygnus cygnus) pair bonding behaviour, Norfolk, England, UK, January.

Robin Chittenden / Whooper swan pair (Cygnus cygnus) Norfolk, England, UK, January.

Robin Chittenden / Whooper Swan (Cygnus cygnus) Norfolk, England, UK, January.

Robin Chittenden / Whooper swan (Cygnus cygnus) Norfolk, England, UK, January.

Robin Chittenden / Whooper swan (Cygnus cygnus) in flight, Norfolk, England, UK, January.

Robin Chittenden / Whooper swan (Cygnus cygnus) in flight, Norfolk, England, UK, January.

David Woodfall / Whooper Swan (Cygnus cygnus) in mist, feeding amongst Bog cotton (Eriophorum angustifolium) and Ragged Robin (Lychnis flos-cuculi) in machair, North Uist, outer Hebrides, Scotland July.

Terry Whittaker / Whooper swans (Cygnus cygnus) on a man-made lake next to an apartment complex. Gardabaer, Reykjavik, Iceland.

Terry Whittaker / Whooper swan (Cygnus cygnus) two in flight, Hornstrandir, Iceland, March.

Nick Upton / Bewick's swan (Cygnus columbiana bewickii) flapping its wings as it stands on a frozen marshland pool, Gloucestershire, UK, February.

Nick Upton / Bewick's swan (Cygnus columbiana bewickii) sliding on ice as it lands on a frozen marshland pool with other swans and Canada geese (Branta canadensis) in the background, Gloucestershire, UK, Febru...

Nick Upton / Bewick's swan (Cygnus columbiana bewickii) sliding on ice after landing on a frozen marshland pool, Gloucestershire, UK, February.

Nick Upton / Bewick's swan (Cygnus columbianus bewickii) in flight overhead, Gloucestershire, UK, February.

Nick Upton / Mute swan (Cygnus olor) cob swimmimng in a drainage channel with others grazing in the background, Tealham Moor, Somerset Levels, UK, January.

Ernie Janes / Mute swan (Cygnus olor) adult male sleeping, England, UK. June.

Ernie Janes / Mute swan (Cygnus olor) attacking Canada goose (Branta canadensis) watched by Coots (Fulica atra) Fleet lagoon, Dorset, England, UK, June.

Martin Grimm/ BIA / Mute Swan (Cygnus olor), Baden-Wurttemberg, Germany

Jeff Foott / Trumpeter Swan (Cygnus buccinator) parents and cygnets, National Elk Refuge, Wyoming

SCOTLAND: The Big Picture / Whooper swan (Cygnus cygnus) wintering in urban park, Hogganfield Loch, Glasgow, Scotland, UK, March.

SCOTLAND: The Big Picture / Whooper swan (Cygnus cygnus) and Mute swan (Cygnus olor) in urban park, Glasgow, Scotland, UK, February.

SCOTLAND: The Big Picture / Close-up of adult whooper swan (Cygnus cygnus) wintering in urban park, Hogganfield Loch, Glasgow, Scotland

Roger Powell / Whooper Swan (Cygnus cygnus) pair swimming in tandem, Syltefjord, Finmark, Norway, June.

Roger Powell / Whooper Swan (Cygnus cygnus) incubating on top of a huge nest made from surrounding aquatic vegetation, with its mate swimming nearby. Limpolo, Sirkka, Finnish Lapland, June.

Roger Powell / Whooper Swan (Cygnus cygnus) incubating on top of a huge nest made from surrounding aquatic vegetation, Borselvefjellet, Porsanger, Finmark, Norway

Will Watson / Llangorse Lake SSSI and SAC featuring Mute Swans (Cynus olor) and Cormorants (Phalacrocorax carbo) and Mynydd Troed in the background, Brecon Beacons National Park, Breconshire, Wales, UK, Spetember 2...

Donald M. Jones / Trumpeter Swan (Cygnus buccinator) parents and juveniles preening, Montana

Loic Poidevin / Mute swan (Cygnus olor) with cygnets on water, Marais d'Olonne, Vendee, France, August.

Loic Poidevin / Mute swan (Cygnus olor) with cygnets on water, Marais d'Olonne, Vendee, France, August.

Nick Upton / Mute swan (Cygnus olor) foraging near reed beds at Ham Wall RSPB reserve with Glastonbury Tor in the background, Somerset Levels, UK, February.

Nick Upton / Bewick's swan (Cygnus columbianus bewicki) preening as it stands in a freshwater lake, Gloucestershire, UK, February.

Nick Upton / Bewick's swan (Cygnus columbianus bewicki) calling as it bathes on a freshwater lake, Gloucestershire, UK, February.

Chase Dekker / Trumpeter Swan (Cygnus buccinator) in misty river, Grand Teton National Park, Wyoming

Mark Carwardine / Mute Swan (Cygnus olor) Slimbridge, Gloucestershire, England, UK, January.

Jack Dykinga / Trumpeter swan (Cygnus buccinator) preening, Firehole River, Yellowstone National Park, Wyoming, USA.

Nick Garbutt / Trumpeter swans (Cygnus buccinator) on the edge of the Upper Yellowstone River. Hayden Valley, Yellowstone National Park, Wyoming, USA. January

Marion Vollborn/ BIA / Whooper Swan (Cygnus cygnus) taking flight on snow, Hokkaido, Japan

Marion Vollborn/ BIA / Whooper Swan (Cygnus cygnus) flying, Hokkaido, Japan

Sean Crane / Trumpeter Swan (Cygnus buccinator) pair on lake in autumn, Tern Lake, Alaska

Konrad Wothe / Mute swans (Cygnus olor) pair displaying, Cygnus olor, winter, Upper Bavaria, Germany. January

Konrad Wothe / Mute swans (Cygnus olor), pair displaying, winter, Upper Bavaria, Germany. January

Guy Edwardes / Whooper swan (Cygnus cygnus) in landscape of Landmannalaugar, Iceland, June.

John Chan / Mute swan (Cygnus olor) feeding on aquatic plants, Bolsa Chica Ecological Reserve, California, USA, March.

Ashley Cooper / Mute Swan (Cygnus olor) in the snow on Lake Windermere, Lake District, England, UK. March.

Loic Poidevin / Mute swan (Cygnus olor), female with cygnets on water. Danube Delta, Romania. May.

Loic Poidevin / Mute swan (Cygnus olor), female with cygnets. Danube Delta, Romania. May.

Oliver Hellowell / Mute swan (Cygnus olor) among large flock, Abbotsbury Swannery, Dorset. England, UK. August.

Oliver Hellowell / Mute Swan (Cygnus olor) preening, Slimbridge Wetlands Centre in Dursley, Gloucestershire, England, UK. December.

Eric Medard / Whooper swan (Cygnus cygnus) flying over water, Sweden. May.

Eric Medard / Whooper swan (Cygnus cygnus) landing on water, Sweden. May.

Eric Medard / Whooper swans (Cygnus cygnus) in dispute Sweden. May.

Eric Medard / Whooper swan (Cygnus cygnus) taking off, Sweden. May.

Eric Medard / Whooper swan (Cygnus cygnus) resting on nest in snow, Sweden. May.

Eric Medard / Whooper swan (Cygnus cygnus) on nest on small island in lake, snowing, Sweden. May.

John Waters / Female Mute Swan (Cygnus olor) swimming with eight cygnets. River Kennet, Hungerford, Berkshire, England, UK, June.

John Waters / Tracking shot from a female Mute Swan (Cygnus olor) to her eight cygnets feeding underwater, River Kennet, Hungerford, Berkshire, England, UK, June.

John Waters / Slow motion clip of a Mallard (Anas platyrhynchos) duckling chasing and catching Mayfly (Ephemeroptera) emerging from the River Kennet, with a Mute swan (Cygnus olor) in the background, Hungerford, Be...

Loic Poidevin / Black swan (Cygnus atratus) swimming in marsh on lle d'Olonne, Vendee, Pays-de-la-Loire, France. April

Ernie Janes / Mute swan (Cygnus olor) wing feathers of i mmature bird before turning white Norfolk, England, UK. December.

Stephen Dalton / Mute swan (Cygnus olor) surrounded by Yellow water lilies (Nuphar lutea) Somerset, England, UK, May.

David Pattyn / Mute swan (Cygnus olor) on a misty morning, with wings raised up in aggressive stance, Valkenhorst Nature Reserve, Valkenswaard, the Netherlands. December