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

Bernard Castelein / Grey-headed gull (Larus cirrocephalus) in flight, Tanji, Gambia.

Bernard Castelein / Grey-headed gull (Larus cirrocephalus) in flight, Tanji, Gambia.

Eric Baccega / Grey headed gull (Chroicocephalus cirrocephalus) flock flying, Queen Elizabeth National Park, Uganda.

Eric Baccega / Grey headed Gull (Chroicocephalus cirrocephalus) on shoreline, Queen Elizabeth National Park, Uganda.

Lou Coetzer / Grey headed / hooded gull (Chroicocephalus cirrocephalus) taking off, Chobe River, Botswana, May.

Lou Coetzer / Grey headed / hooded gull (Chroicocephalus cirrocephalus) exiting water with worm in beak, Chobe River, Botswana, May.

Lou Coetzer / Grey headed / hooded gull (Chroicocephalus cirrocephalus) taking off, Chobe River, Botswana.

Lou Coetzer / Grey headed / hooded gull (Chroicocephalus cirrocephalus) taking off with worm whilst screaming defensively, Chobe River, Botswana.

Lou Coetzer / Grey hooded / headed gull (Chroicocephalus cirrocephalus) taking off while exiting water, Chobe River, Botswana.

Mike Wilkes / Grey-headed gullls (Larus cirrocephalus poiocephalus) feeding on discarded fish offal, Tanji Beach, Gambia, west Africa.

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

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

Mike Wilkes / Grey headed gull {Chroicocephalus cirrocephalus} Gambia

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

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.

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

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

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

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

Pete Oxford / Grey hooded gull {Chroicocephalus cirrocephalus} Argentina

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

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

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

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

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