Claudio Contreras / Heermann's Gull (Larus heermanni) in flight, Ensenada, Baja California Peninsula, Mexico, December.

Mary McDonald / Flock of Gray-headed Gulls (Chroicocephalus cirrocephalus) flying over Lake Nakuru, Kenya, East Africa

Gerrit Vyn / Flock of Heermann's Gulls (Larus heermanni) standing on intertidal rocks. Jefferson County, Washington, USA, August.

Dietmar Nill / Grey heron (Ardea cinerea) with fish being attacked by Gull, Germany, winter

Mark Bowler / Large flock of roosting Grey gulls (Leucophaeus modestus) on beach with coastal fog over the Atacama Desert on the Peruvian coast, Paracas National Park, Peru.

Robin Chittenden / Grey headed gull (Chroicocephalus cirrocephalus) in shallow water, Western Division, Gambia, March

Robin Chittenden / Grey headed gull (Chroicocephalus cirrocephalus) in flight, Western Division, Gambia, March

Robin Chittenden / Grey headed Gull (Chroicocephalus cirrocephalus) on shoreline, Western Division, Gambia, March

Nick Upton / 2020VISION / Lesser black-backed gull (Larus fuscus) flying up from pond with eyes fixed on some bread thrown by a tourist, Victoria park, Bath, UK, June.

Laurent Geslin / Grey headed gull (Chroicocephalus cirrocephalus) in flight, Moremi NP, Botswana

Terry Whittaker / 2020VISION / Woman feeding gulls and Grey heron (Ardea cinerea) with fish from supermarket, River Tame, Reddish Vale Country Park, Stockport, Greater Manchester, UK, December 2010

Terry Whittaker / 2020VISION / Grey heron (Ardea cinerea) amongst pigeons, coots, seagulls and swans in parkland, Regent's Park, London, UK, February 2011

Murray Cooper / Grey-headed Gull (Larus cirrocephalus) pair courting, Ecuador

Mark Bowler / Grey gulls (Leucophaeus modestus) on beach, Paracas National Park, near Pisco, Ica, Peru, June 2007

Konrad Wothe / Grey Heron (Ardea cinerea) group of five competing with a lone gull for a fih, Usedom, Germany

Konrad Wothe / Grey Heron (Ardea cinerea) and young Great Black-backed Gull (Larus marinus), Usedom, Germany

Jabruson / Grey headed gull (Chroicocephalus cirrocephalus) standing on log in water, Lake Nakuru NP, Kenya

Hermann Brehm / Grey headed gull (Chroicocephalus cirrocephalus) scavenging mongoose roadkill, Serengeti NP, Tanzania

Mike Wilkes / Grey headed gull {Chroicocephalus cirrocephalus} Gambia

Pete Oxford / Grey hooded gull flying {Chroicocephalus cirrocephalus} Argentina

Hanne & Jens Eriksen / Grey Gull {Leucophaeus modestus} profile on beach, Antofagasta, Chile.

Hanne & Jens Eriksen / Grey headed gull (Chroicocephalus cirrocephalus) in water, False Bay, South Africa

Pete Oxford / Grey / Gray-headed Gulls {Chroicocephalus cirrocephalus} San Pablo Beach, Guayas, Ecuador.

Pete Oxford / Gulls and Terns flocking on beach, Gray / Grey-hooded Gull {Larus cirrocephalus} Laughing Gull {Larus atricilla} Sandwich Tern {Sterna sandvicensis}and Elegant Tern {Sterna elegans} San Pablo Beach, G...

Anup Shah / Juvenile Grey headed gull ? {Chroicocephalus cirrocephalus} feeding on Lesser flamingo carcass, East Africa.

Anup Shah / Grey headed gull {Chroicocephalus cirrocephalus} taking-off, Lake Nakuru NP, Kenya

Gabriel Rojo / Grey headed gull on water {Chroicocephalus cirrocephalus} La Pampa, Argentina Macachin, pampas

Ben Osborne / Grey gull {Leucophaeus modestus} feeds on Flat backed turtle hatchling, Crab Is, Australia

Gabriel Rojo / Grey headed gull flying {Chroicocephalus cirrocephalus} La Pampa, Argentina Macachin, pampas

Pete Oxford / Grey hooded gull {Chroicocephalus cirrocephalus} Argentina

Pete Oxford / Grey hooded gull landing {Chroicocephalus cirrocephalus} Argentina

Mike Wilkes / Grey-headed gull (Chroicocephalus cirrocephalus) standing on shore with food in beak, The Gambia, December

Mike Wilkes / Flock of Grey-headed gulls (Chroicocephalus cirrocephalus) on water, The Gambia, December

Mike Wilkes / Grey-headed gull (Chroicocephalus cirrocephalus) in flight over water, with food in beak, The Gambia, December

JIM CLARE / Grey gull {Leucophaeus modestus} on ground nest, Atacama Desert, Chile, South America

Ben Osborne / Baby Flat backed turtle {Chelonia depressa} predated by Grey gull Crab Is Australia