Ole Jorgen Liodden / Arctic tern (Sterna paradisaea) attacking an Arctic Fox (Vulpes / Alopex lagopus) protecting its nest site, Spitsbergen, Svalbard, Norway. Highly commended, MAMMALS, GDT 2011 competition

Anup Shah / African fish eagle {Haliaeetus vocifer} defends Lesser flamingo carcass from Marabou storks {Leptoptilos crumeniferus}, Lake Nakuru, Kenya.

Anup Shah / African fish eagle {Haliaeetus vocifer} fighting Marabou storks {Leptoptilos crumeniferus} over Lesser flamingo carcass, Lake Nakuru, Kenya.

John Sparks / David Attenborough with mountain gorillas, on location during filming for BBC 'Life on Earth' series in Rwanda 1978

Marie Read / Western Grebe (Aechmorphus occidentalis), pair during 'rushing' courtship display in which they run across water's surface in synchrony, near Escondido, California, USA, January.

Marie Read / Wood Ducks (Aix sponsa), females behave aggressively toward a male (second from right) that is trying to join them on a floating log, autumn, New York, USA, October.

Marie Read / American avocets (Recurvirostra americana) two during aggressive (territorial) encounter, Bear River Migratory Bird Refuge, Utah, USA, May.

Ingo Arndt / King Penguin (Aptenodytes patagonicus) dispute on beach, Volunteer Point, Falkland Islands, February

Ingo Arndt / King Penguins (Aptenodytes patagonicus) dispute while coming ashore, Salisbury Plain, South Georgia Island, February

Ingo Arndt / Thick billed ravens interacting {Corvus crassirostris} Simien NP, Ethiopia, East Africa

Mark Hamblin / 2020VISION / Two male Black grouse (Tetrao tetrix) fighting at lek site, with mountain backdrop, Cairngorms NP, Scotland, UK, April 2010

Mark Hamblin / 2020VISION / Jackdaw (Corvus monedula) pair at their nest hole, one pecking the other for attention, the other quivering its tail, Inverness-shire, Scotland, April 2011