Erlend Haarberg / Razorbill (Alca torda) male and female mating, Langanes Peninsula, Iceland, May

Peter Blackwell / Secretary bird (Sagittarius serpentarius) in flight with nesting material, Masai Mara NP, Kenya

Shattil & Rozinski / Columbian sharp tailed grouse {Tympanuchus phasianellus} males fighting at lek, USA

Richard Du Toit / Male Hippopotamus fighting over female {Hippopotamus amphibius} Kruger NP South Africa