Edwin Giesbers / Common red soldier beetle (Rhagonycha fulva) pair mating amongst flowers. The Netherlands. July.

Simon Littlejohn / Pair of Griffon vultures (Gyps fulvus) mating, Andalusia, Spain, June.

Dave Watts / Hoopoe (Upupa epops) male and female pair visiting nest to feed chicks, France

Brian Bevan / Male European cuckoo (Cuculus canorus) trying to mate with a decoy female, used as part of a scientific study, Bedfordshire, England, UK, May.

Brian Bevan / Male European cuckoo (Cuculus canorus) trying to mate with a decoy female, used as part of a scientific study, Bedfordshire, England, UK, May.

Brian Bevan / Male European cuckoo (Cuculus canorus) calling to another male, before flying off in response to a female, Bedfordshire, England, UK, May.

Konrad Wothe / Two male Lawes' parotia birds of paradise (Parotia lawesii) hopping on its display ground, with females watching nearby, Papua New Guinea.

Tui De Roy / Galapagos hawk (Buteo galapagoensis) landing on mating pair of Galapagos giant tortoise (Chelonoidis vandenburgh) Alcedo Volcano, Isabela Island, Galapagos.

Tui De Roy / Wolf giant tortoise (Chelonoidis becki) two males fight briefly over mating rights. Wolf Volcano, Isabela Island, Galapagos

Dave Bevan / Pair of Grey wagtails (Motacilla cinerea) feeding nestlings and removing faecal sacs before flying out of frame, Carmarthenshire, Wales, UK, June.

John Cancalosi / Sonoran desert toad (Incilius alvarius) pair mating, with trail of spawn in water. Arizona, USA.

Matthew Maran / Red fox (Vulpes vulpes) dog interacting with a vixen in an urban garden. North London, UK. June.

Matthew Maran / Red fox (Vulpes vulpes) dog interacting with a vixen in an urban garden. North London, UK. July.

Matthew Maran / Red fox (Vulpes vulpes) cub defending its kill,a large Brown rat (Rattus norvegicus) from another cub, North London, UK. August. Highly commended in the Behaviour : Mammals Category of the Wildlife Ph...

Morley Read / Slow motion clip of a group of male Mallards (Anas platyrhynchos) competing violently to mate with a single female, Cornwall, England, UK, May 2018.

Alex Mustard / Pair of Western clown anemonefish (Amphiprion ocellaris) spawning orange eggs on the rock beneath their Magnificent sea anemone (Heteractis magnifica) home on a coral reef. This photo shows the larger...

Ben Gillett / Slow motion clip of a female Appaloosa horse grooming a male, Bristol, England, UK, May.

John Chan / Two male Southern Pacific rattlesnakes (Crotalus oreganus helleri) fighting during mating season. This behaviour is known as a "combat dance", and is used to determine dominance and the right to mate...

SCOTLAND: The Big Picture / RF - Brown hare, (Lepus europaeus) male pursuing female that is in season, Islay, Scotland, UK., March (This image may be licensed either as rights managed or royalty free.)

SCOTLAND: The Big Picture / RF - Brown hare, (Lepus europaeus), male and female displaying courtship behaviour, Islay, Scotland, UK., March (This image may be licensed either as rights managed or royalty free.)

Marie Read / Black-necked stilts (Himantopus mexicanus) pair performing post-copulatory display (as copulation ends, the male slides off the female leaving his wings draped over her and crossing his bill with hers...

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.

David Tipling / Common European adder (Vipera berus) two males fighting over a female. Holt, North Norfolk, England, UK. April

David Tipling / Common European adder (Vipera berus) two males fighting over a female, Holt, North Norfolk, England, UK. April

David Tipling / Common European adder (Vipera berus) two males fighting over a female, Holt, North Norfolk, England, UK. April.

Espen Bergersen / Aerial shot of Killer whales (Orcinus orca) near the surface, showing mating behaviour, Troms, Norway, August.

Nick Upton / Pair of White storks (Ciconia ciconia) mating on their nest, Knepp Castle Estate, Sussex, England, UK, April. This is the first recorded instance of White storks nesting in the UK for several hundreds...

Nick Upton / Pair of White storks (Ciconia ciconia) arranging nest material on their nest, Knepp Castle Estate, Sussex, England, UK, April. This is the first recorded instance of White storks nesting in the UK for...

Nick Upton / Pair of White storks (Ciconia ciconia) arranging nest material on their nest, Knepp Castle Estate, Sussex, England, UK, April. This is the first recorded instance of White storks nesting in the UK for...

Nick Upton / White stork (Ciconia ciconia) pair mating on their nest at sunset, Knepp estate, Sussex, UK, April 2019. This is the first recorded instance of White storks nesting in the UK for several hundreds of y...

Nick Upton / White stork (Ciconia ciconia) pair performing an up-down display with bill clattering on their nest in an Oak tree, Knepp estate, Sussex, UK, April 2019. This is the first recorded instance of White s...

Nick Upton / White stork (Ciconia ciconia) male landing with nest material and joining his mate on their nest in an Oak tree at sunset, Knepp estate, Sussex, UK, April 2019. This is the first recorded instance of...

David Gallan / Cameratrap video of a male Superb lyrebird (Menura novaehollandiae) courting female on display mound, Australia, July.

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

Michael Hutchinson / Pair of Marsh fritillary butterflies (Euphydryas aurinia) courting on a Buttercup (Ranunculus), Devon, England, UK, June.

Michael Hutchinson / Pair of Marsh fritillary butterflies (Euphydryas aurinia) courting on a Buttercup (Ranunculus), Devon, England, UK, June.

Michael Hutchinson / Pair of Marsh fritillary butterflies (Euphydryas aurinia) mating, Devon, England, UK, June.

Michael Hutchinson / Close-up of a pair of Marsh fritillary butterflies (Euphydryas aurinia) mating, showing tips of abdomens, Devon, England, UK, June.

Michael Hutchinson / Close-up of a pair of Marsh fritillary butterflies (Euphydryas aurinia) mating, shot tilt downs, Devon, England, UK, June.

Michael Hutchinson / Male Marsh fritillary butterfly (Euphydryas aurinia) displaying to a female on a Buttercup (Ranunculus) flower, Devon, England, UK, June.

John Chan / Male California least tern (Sternula antillarum browni) presenting fish offering to female during mating, Huntington Beach, California, USA, May.

John Cancalosi / American toads (Anaxyrus americanus), several males competing to mate with female, Maryland, USA, April.

Tony Wu / Zoarchias major eelpouts. (Zoarchias major) The orange individual is female, the one in the hole is male. The female has approached the male, curled around him, attempting to dislodge the male from th...

Stefan Christmann / Emperor penguin (Aptenodytes forsteri), pair mating. Atka Bay, Antarctica. May.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) pair practising incubating with a snowball. Atka Bay, Antarctica. May.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) pair practising incubating with a snowball. Atka Bay, Antarctica. May. Winner of the Polar Passion Category of the Nature's Best Photography Competition 2019.

Stefan Christmann / Emperor penguin (Aptenodytes forsteri) pair in courtship, on sea ice. Atka Bay, Antarctica. May.