Tony Wu / Sperm whale (Physeter macrocephalus), ten swimming together in gathering of more than 50 individuals. Whales with flatulence and defecating. Sri Lanka.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) colony huddling, males incubating eggs, on sea ice under full moon in polar night. Atka Bay, Antarctica. July 2017.

Brian Bevan / Pair of Reed warblers (Acrocephalus scirpaceus) feeding young at nest, Bedfordshire, England, UK, July.

Dave Bevan / Female Blackbird (Turdus merula) feeding chicks at nest, removing faecal sacs, Carmarthenshire, Wales, UK, June.

Dave Bevan / Male Great spotted woodpecker (Dendrocopos major) entering nest hole and leaving with a faecal sac, Carmarthenshire, Wales, UK, June.

Neil Aldridge / Dung beetle (Scarabaeidae) pushing ball of dung on Venetia Limpopo Reserve, Limpopo Province, South Africa.

Morley Read / Timelapse of a King swallowtail (Papilio thoas) butterfly caterpillar drinking water from the surface of a leaf, ), showing bird dropping camouflage, Napo Province, Ecuadorian Amazon. (non-ex)

Morley Read / King swallowtail (Papilio thoas) butterfly caterpillar, showing bird dropping camouflage, Napo Province, Ecuadorian Amazon. (non-ex)

Mike Read / Rock ptarmigan (Lagopus mutus) droppings, Cairngorms National Park, Highland Region, Scotland, UK, May.

JIM CLARE / Nests of Guanay cormorants, (Phalacrocorax bougainvilliiorum) after breeding has finished, shows build-up of guano around the nest. The colonies are strictly protected and the guano will be harvested...

JIM CLARE / Nest of Guanay cormorants, (Phalacrocorax bougainvilliiorum), after breeding has finished, shows build-up of guano around the nest. The colonies are strictly protected and the guano will be harvested...

JIM CLARE / Balls formed in and around nests of guanay cormorants (Phalacrocorax bougainvilliiorum) as they walk over moist ground and coat loose stones, or even eggs, with guano. Each of the balls usually has a...