John Chan / American avocet (Recurvirostra americana) foraging in salt marsh, Southern California, USA.

John Waters / Large murmuration of Common starlings (Sturnus vulgaris) swirling over reedbed roost at sunset, Ham Wall RSPB Reserve, Somerset, England, UK, January.

John Waters / Large flock of Common starlings (Sturnus vulgaris) swirling over reedbed roost at dusk, Ham Wall RSPB Reserve, Somerset, England, UK, November.

John Waters / Large flock of Common starlings (Sturnus vulgaris) swirling over reedbed roost at dusk, Ham Wall RSPB Reserve, Somerset, England, UK, November.

Michael Hutchinson / Marsh fritillary butterfly (Euphydryas aurinia) flying and landing on a Buttercup (Ranunculus), Devon, England, UK, June.

Michael Hutchinson / Pair of Marsh fritillary butterflies (Euphydryas aurinia) courting on a Buttercup (Ranunculus), Devon, England, UK, June.

Michael Hutchinson / Pair of Marsh fritillary butterflies (Euphydryas aurinia) courting on a Buttercup (Ranunculus), Devon, England, UK, June.

Michael Hutchinson / Marsh fritillary butterfly (Euphydryas aurinia) nectaring from a Buttercup (Ranunculus) before taking off, Devon, England, UK, June.

Michael Hutchinson / Pair of Marsh fritillary butterflies (Euphydryas aurinia) mating, Devon, England, UK, June.

Michael Hutchinson / Close-up of a pair of Marsh fritillary butterflies (Euphydryas aurinia) mating, showing tips of abdomens, Devon, England, UK, June.

Michael Hutchinson / Close-up of a pair of Marsh fritillary butterflies (Euphydryas aurinia) mating, shot tilt downs, Devon, England, UK, June.

Michael Hutchinson / Male Marsh fritillary butterfly (Euphydryas aurinia) displaying to a female on a Buttercup (Ranunculus) flower, Devon, England, UK, June.

Bernard Castelein / Bulrush (Typha latifolia) Klein Schietveld, Brasschaat, Belgium

Bernard Castelein / Trees reflected in marshland, Peerdsbos, Brasschaat, Belgium

Francisco Marquez / Round up of wild mares and foals from marshland to the corrals of the town. Donana National Park, Spain. September 2014.

Guy Edwardes / Saltmarsh. Isle of Harris, Scotland, UK. March, 2015.

Guy Edwardes / Saltmarsh on the Isle of Harris, Outer Hebrides, Scotland, UK. November 2016.

Dave Bevan / Grey plover (Pluvialis squatarola) eating a marine flatworm, Norfolk, England, UK, February.

Dave Bevan / Bittern (Botaurus stellaris) hunting and catching a fish, Suffolk, England, UK, October.

John Waters / Mixed flock of Wigeon (Anas penelope) and Northern lapwings (Vanellus vanellus) disturbed by hunting Marsh Harrier (Circus aeruginosus), Greylake RSPB Reserve, Somerset Levels, England, UK, December.

John Waters / Slow motion clip of a flock of Northern lapwings (Vanellus vanellus) flying over a flooded marsh, Catcott Lows Nature Reserve, Somerset Levels, England, UK, December.

Jeff Vanuga / White horses of the Camargue galloping through marshes in the Camargue, France. April.

Jeff Vanuga / White horse of the Camargue galloping through marshes in the Camargue, France. April.

Jeff Vanuga / White horses of the Camargue galloping through marshes in the Camargue, France. April.

Ernie Janes / Aerial view of boats in East Fleet, with Pinewoods caravan park, and salt marshes on the coast of Norfolk, England, UK, February 2009.

Ernie Janes / Sea lavender (Limonium vulgare) growing in saltmarsh, with Blakeney Village in the background, Norfolk, England, UK, July.

Gabriel Rojo / Marsh deer (Blastocerus dichotomus) male with Cattle tyrant (Machetornis rixosus) on back, Ibera Marshes, Corrientes Province, Argentina.

Gabriel Rojo / Black caiman (Melanosuchus niger) on shore, Ibera Marshes, Corrientes Province, Argentina

Gabriel Rojo / Cattle tyrant (Machetornis rixosus) perched on capibara¶ÿ (Hydrochoerus hydrochaeris) Ibera Marshes, Corrientes Province, Argentina

Nick Upton / Panning shot of partially flooded pastureland with large flocks of Wigeon (Anas penelope), Lapwings (Vanellus vanellus) and Golden plover (Pluvialis apricaria) in flight, Gloucestershire, England, UK,...

Nick Upton / Panning shot of a flock of Lapwings (Vanellus vanellus) landing on partially flooded pastureland near resting Black-tailed godwits (Limosa limosa) and grazing Wigeon (Anas penelope), Gloucestershire,...

Loic Poidevin,Loic Poidevin / Short-eared Owl (Asio flammeus) diving at prey, Breton Marsh, West France, April

George Sanker / Freshwater marshland, Acadia National Park, Maine. Novemebr 2012

Jean E. Roche / Flock of Greater flamingos (Phoenicopterus ruber) sleeping in water, Camargue, Southern France, September 2008

Jean E. Roche / Aerial view of wind turbines of wind farm on the Camargue, Port Saint Louis du Rhone, Southern France, September 2008

Juan Carlos Munoz / Aerial view saltmarshes of Bahia de Cadiz Natural Park, Huelva, Andalucia, Spain, March 2008

Juan Carlos Munoz / Aerial view river tributaries and saltmarshes of Bahia de Cadiz Natural Park, Huelva, Andalucia, Spain, March 2008

Loic Poidevin / Short eared owl (Asio flammeus) in flight over marshland, Vendee, west France, April

Niall Benvie / 2020VISION / Thrift (Armeria maritima) flowering on saltmarsh at the south end of Achnahaird Bay, Coigach and Assynt, Sutherland, Scotland, UK, June 2011

Grzegorz Lesniewski / Eurasian Curlew (Numenius arquata) in wet grass lit by dawn light. Biebrza National Park, Biebrza marshes, Poland, May.

Ernie Janes / Old dinghy on saltmarshes, Brancaster, Norfolk, UK, March 2009

Nick Upton / Large flock of Wigeon (Anas penelope) swimming and standing on flooded marshland on a foggy winter day with a small flock of Lapwings (Vanellus vanellus) in the background. Greylake RSPB reserve, Some...

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

Wild Wonders of Europe / López / Aerial view of marshes with Seaweed exposed at low tide, Bahía de Cádiz Natural Park, Cádiz, Andalusia, Spain, February 2009.

Wild Wonders of Europe / López / Aerial view of marshes at low tide, Bahía de Cádiz Natural Park, Cádiz, Andalusia, Spain, February 2009

David Tipling / Common buzzard (Buteo buteo) in flight, captive, Gloucestershire, UK

Wild Wonders of Europe / della Ferrera / Cultivated part of the lower Neretva river delta with a sinkhole in marshland surrounded by Reeds (Phragmites sp) Dalmatia region, Croatia, May 2009

Wild Wonders of Europe / della Ferrera / Sinkhole in marshland covered in Reeds (Phragmites sp) near the lower Neretva river delta, Dalmatia region, Croatia, May 2009