Marie Read / American oystercatcher (Haematopus palliatus) adult feeding chick, Long Island, New York, USA. June.

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

Alan Murphy/ BIA / Northern Caracara (Caracara cheriway) pair fighting, Texas

Alan Murphy/ BIA / Belted Kingfisher (Megaceryle alcyon) fishing, Texas

Alan Murphy/ BIA / Baltimore Oriole (Icterus galbula) males fighting, Texas

Alan Murphy/ BIA / Baltimore Oriole (Icterus galbula) males fighting, Texas

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) two adults with chicks, age 9-12 weeks, Atka Bay, Queen Maud Land, Antarctica. October.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) two adults with chicks,Atka Bay, Queen Maud Land, Antarctica. October.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) Atka Bay, Queen Maud Land, Antarctica. October.

Stefan Christmann / Adelie penguin (Pygoscelis adeliae) nesting pair, Atka Bay, Queen Maud Land, Antarctica, December.

David Gallan / Male Satin bowerbird (Ptilonorhynchus violaceus) courting female on suburban street verge, bower filled with blue plastic, Australia, October 2018.

Markus Varesvuo / Jay (Garrulus glandarius), two fighting in mid-air with another observing. Norway. October.