Terry Whittaker / Common murre / guillemot (Uria aalge) and Black-legged kittiwake (Rissa tridactyla) eggs in box and egg boxes. Collected from Skoruvikurbjarg cliffs, Langanes Peninsula, Iceland. May 2018.

Ernie Janes / Pacific gulls (Larus pacificus) in flight over beach Tasmania, Australia.

Ernie Janes / Pacific gull (Larus pacificus) feeding on beach, Tasmania, Australia.

Ernie Janes / Pacific gull (Larus pacificus) feeding on beach, Tasmania, Australia.

Hermann Brehm / Large-billed Tern (Phaetusa simplex) Pantanal, Brazil

Philippe Clement / Kittiwakes (Rissa tridactyla), Common guillemots (Uria aalge) and Razorbills (Alca torda) nesting on rock ledges in breeding colony, Fowlsheugh RSPB Reserve, Aberdeenshire, Scotland, UK, May

Cyril Ruoso / Seabirds including Black-legged kittiwakes (Rissa tridactyla), Brunnich's guillemots (Uria lomvia), Common guillemots (Uria aalge) and Atlantic suffins (Fratercula arctica) flying over sea near Latrab...

Cyril Ruoso / Seabirds, including Black-legged Kittiwake (Rissa tridactyla), Brunnich's guillemots (Uria lomvia), Common guillemots (Uria aalge) and Atlantic puffins (Fratercula arctica) nesting on cliff face and f...

Hermann Brehm / Large-billed tern (Phaetusa simplex) with mouth wide open, Pantanal, Brazil.

Staffan Widstrand / Kittiwakes (Rissa tridactyla), Common guillemots (Uria algae) and Brunnichs guillemots (Uria lomvia) Hornoya Island, Varanger Peninsula, Norway, March.

Staffan Widstrand / Kittiwakes (Rissa tridactyla) and Guillemots (Uria algae) and Brunnichs guillemots (Uria lomvia) Hornoya Island, Varanger Peninsula, Norway, March.

Pete Oxford / Large-billed tern (Phaetusa simplex) at edge of water. Northern Pantanal, Mato Grosso, Brazil.

Ben Cranke / Large-billed Tern (Phaetusa simplex) pair, perched on a tree log, Mato Grosso, Pantanal, Brazil. August.

Angelo Gandolfi / Large-billed tern (Phaetusa simplex) in flight by coast, Santa Catarina, Brazil, September.

Angelo Gandolfi / Large-billed terns (Phaetusa simplex) in non-breeding plumage (above) and breeding plumage (below), Santa Catarina, Brazil, September.

Luiz Claudio Marigo / Large-billed Tern (Phaetusa simplex) in Lake Mamiraua, Mamiraua Sustainable Development Reserve, Alvaraes, Amazonas State, Northern Brazil.

Robin Chittenden / Large-billed tern (Phaetusa simplex) in flight, Trinidad, April.

Robin Chittenden / Large-billed tern (Phaetusa simplex) perched on post, Trinidad, April

Shattil & Rozinski / Ring-billed gulls (Larus delawarensis) large flock in flight and on water, Cherry creek state park, Denver, Colorado, USA, January

Marie Read / Red-breasted Merganser (Mergus serrator) with large fish, trying to escape attempted robbery by Ring-billed Gull (Larus delawarensis). Bolsa Chica Ecological Reserve, California, USA, February.

Marie Read / Red-breasted Merganser (Mergus serrator) with large fish, trying to escape attempted robbery by Ring-billed Gull (Larus delawarensis), Bolsa Chica Ecological Reserve, California, USA, February.

Pete Oxford / Two Large-billed terns (Phaetusa simplex) standing at water's edge, one with fish prey in beak, Pantanal, Mato Grosso, Brazil.

Doug Gimesy / Pacific gull (Larus pacificus) on water, Sandringham, Victoria, Australia.

Doug Gimesy / Pacific gull (Larus pacificus) portrait, Port Philip Bay, Sandringham, Victoria, Australia.

Doug Gimesy / Pacific gull (Larus pacificus) walking through shallow water, foraging in intertidal rocks, Port Philip Bay, Sandringham, Victoria, Australia.

Doug Gimesy / Pacific gull (Larus pacificus) feeding on a mussel on intertidal rocks, Port Philip Bay, Sandringham, Victoria, Australia.

Doug Gimesy / Pacific Gull (Larus pacificus), juvenile, in flight, Victoria, Australia.

Doug Gimesy / Pacific Gull (Larus pacificus), juvenile, in flight, Victoria, Australia.

Doug Gimesy / Pacific gull (Larus pacificus) holding sea urchin (Echinoidea) in its beak on edge of shore line, Victoria, Australia.

Doug Gimesy / Pacific Gull (Larus pacificus), juvenile, on edge of shore line, Victoria, Australia.

Doug Gimesy / Young Pacific gull (Larus pacificus) holding and feeding on fish whilst in flight low over ground. Victoria, Australia.

Doug Gimesy / Juvenile Pacific gull (Larus pacificus) on the intertidal zone rocks with two Silver gulls (Chroicocephalus novaehollandiae) in background, Sandringham, Victoria, Australia.

Doug Gimesy / Juvenile Pacific gull (Larus pacificus) feeding on fish on the intertidal zone rocks, Sandringham, Victoria, Australia.

Doug Gimesy / Juvenile Pacific gull (Larus pacificus) flying with fish in beak, Sandringham, Victoria, Australia.

Doug Gimesy / Juvenile Pacific gull (Larus pacificus) eating fish on the intertidal zone rocks, Sandringham, Victoria, Australia.

Doug Gimesy / Juvenile Pacific gull (Larus pacificus) flying with fish in beak, Sandringham, Victoria, Australia.

Guy Edwardes / Tourist boat negotiating sea ice in Nemuro Strait - feeding Steller's (Haliaeetus pelagicus) and White-tailed eagles (Haliaeetus albicilla) with gulls and Jungle crows (Corvus macrorhynchos), Hokk...

Doug Gimesy / Pacific gull (Larus pacificus) in flight on a cloudy day. Sandringham, Victoria, Australia.

Doug Gimesy / Pacific gull (Larus pacificus) in flight on a cloudy day. Sandringham, Victoria, Australia.

Dave Bevan / Mixed breeding colony of Northern gannets (Morus bassanus), Common guillemots (Uria aalge), Razorbills (Alca torda) and Black legged kittiwakes (Rissa tridactyla) on a cliff, Yorkshire, England, UK, M...

Dave Bevan / Common guillemots (Uria aalge) crowded together on nesting ledge in a breeding colony, Yorkshire, England, UK, May.

Sylvain Cordier / Large-billed tern (Phaetusa simplex) , in flight Pantanal, Mato Grosso, Brazil.