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

Ramon Navarro / Male European bee eater (Merops apiaster) offering insect to female as part of a courtship display, before mating, Seville, Spain, May.

Ramon Navarro / Male Spanish ibex (Capra pyrenaica) displaying to female on mountain side, Torcal de Antequera Nature Reserve, Malaga, Spain, October.

Denis-Huot,Denis-Huot / Ostrich (Struthio camelus) female and male with chicks, Masai-Mara Game Reserve, Kenya

LYNN M. STONE / Great Egrets (Ardea alba) preening their breeding plumage, at nest. Osceola County, Florida, USA, March.

Alex Mustard / Rock beauty angelfish (Holacanthus tricolor) pair at dusk performing their courtship dance with the larger male circling the female, Georgetown, Grand Cayman, Cayman Islands, British West Indies. Cari...

Ross Hoddinott / 2020VISION / Common blue damselfly {Enallagma cyathigerum}, mating pair, Little Bradley Ponds, Devon, UK. July. 2020VISION Book Plate.

Ross Hoddinott / 2020VISION / Common blue damselfly {Enallagma cyathigerum}, mating pair, Little Bradley Ponds, Devon, UK. July

Daniel Heuclin / Pyrenean mountain newt / brook salamander (Calotriton / Euproctus asper) mating pair, captive, from Pyreneen mountains, France and Spain, near threatened

Juergen Freund / Green turtles (Chelonia mydas) mating over coral reef, Sipadan Island, Sabah, Malaysia, June, Endangered species

Ben Hall / 2020VISION / Irish Damselfly (Coenagrion lunulatum) pair mating, Montiagh's Moss, County Antrim, Northern Ireland, June. 2020VISION Book Plate.

Peter Cairns / 2020VISION / Pair of Gannets (Morus bassanus) mutual preening, Bass Rock, Firth of Forth, Scotland, UK, June. Photographer quote: 'I never get tired of watching gannets. This pair who momentarily lined up in perfe...

Charlie Summers / King / Imperial Cormorants (Phalacrocorax albiventer) breeding pair display courtship behaviour in the form of a ritual dance at their nesting site on Saunders Island, Falkland Islands

Wild Wonders of Europe / Hermansen / Gannet (Morus bassanus) courtship, Saltee Islands, County Wexford, Republic of Ireland, June 2009

Wild Wonders of Europe / Hermansen / Gannets (Morus bassanus) pair, Saltee Islands, County Wexford, Republic of Ireland, June 2009

Wild Wonders of Europe / Hermansen / Gannet (Morus bassanus) courtship, Saltee Islands, County Wexford, Republic of Ireland, June 2009

Wild Wonders of Europe / Bartocha / Common red soldier beetle (Rhagonycha fulva) pair mating on Wild carrot (Daucus carota carota) flower, Hvblege, Mn, Denmark, July 2009

Wild Wonders of Europe / Green / Northern gannets (Morus bassanus) pair at nest, Saltee Islands, Republic of Ireland, June 2009

Wild Wonders of Europe / Green / Northern gannets (Morus bassanus) displaying, Saltee Islands, Republic of Ireland, May 2008

Wild Wonders of Europe / Möllers / Nine-spotted moth (Amata / Syntomis phegea) pair mating, San Marino, May 2009

Wild Wonders of Europe / Allofs / Greater flamingos (Phoenicopterus roseus) mating, in lagoon, Pont Du Gau, Camargue, France, April 2009

Wild Wonders of Europe / Allofs / Greater flamingo (Phoenicopterus roseus) pair mating, in lagoon, Pont Du Gau, Camargue, France, April 2009

Tim Laman / Magnificent Bird of Paradise (Cicinnurus magnificus) male displaying to female at lek, Arfak Mountains, Papua, Indonesia.

Tim Laman / Magnificent Bird of Paradise (Cicinnurus magnificus) male displaying to female at lek display site, Arfak Mountains, Papua, Indonesia.

Guy Edwardes / Northern gannets {Morus bassanus} pair in courtship display, Great Saltee, Co. Wexford, Republic of Ireland, June

Edwin Giesbers / Northern gannet (Morus bassanus) pair, courtship, Heligoland, Germany

Orsolya Haarberg / Northern gannet (Morus bassanus) colony, courtship, Seabird cliff, Langanes peninsula, Iceland, July 2008

Steven Kazlowski / Polar bear (Ursus maritimus) pair walking amongst rough ice on the frozen eastern Chukchi Sea, Arctic Alaska

Ross Hoddinott / Five-spot burnet moths {Zygaena trifolii} mating on Pyramidal orchid {Anacamptis pyramidalis} Cornwall, UK.

Colin Seddon / Burmese brown tortoises mating {Manuria emys} captive

Fabio Liverani / Alpine newt courting pair {Triturus alpestris} male on right, Italy

Mark Hamblin / 2020VISION / Common toads (Bufo bufo) in amplexus in spawning pond, Cairngorms NP, Scotland, UK, April 2011

Mark Hamblin / 2020VISION / Jackdaw (Corvus monedula) pair on branch looking around, the right-hand bird cleaning its beak, the left-hand bird ruffling its feathers, Inverness-shire, Scotland, UK, April 2011

Andy Jackson / 2020VISION / Pair of Cuckoo wrasse (Labrus mixtus) and a Ballan wrasse (Labrus bergylta) feeding on a Sea urchin (Echinoidea), Lochgary Wreck, Kirkwall, Orkney, Scotland, UK, June.

Dietmar Nill / Male and female Golden oriole (Oriolus oriolus)settling at nest and vocalising, before the male takes flight, Bulgaria, June

Dietmar Nill / Pair of Northern goshawks (Accipiter gentilis) copulating in a tree, Berlin, Germany, February

Mark Hamblin / 2020VISION / Jackdaw (Corvus monedula) pair looking into their nest hole and quivering their tales, Inverness-shire, Scotland, April 2011

Andy Rouse / 2020VISION / Pair of Ospreys (Pandion haliaetus) mating on a nesting platform, Cors Dyfi Montgomeryshire Wildlife Trust Reserve, Dyfi Estuary, Ceredigion, Wales, UK, April 2012. Taken with a Schedule 1 license fro...

Markus Varesvuo / House Bunting (Emberiza sahari) female and male perched on ventilation ledges in building, Morocco, February

Markus Varesvuo / Black-headed Gull (Chroicocephalus ridibundus) pair, courtship, Finland, April

Ammonite / Pair of Mantled howler monkeys (Alouatta palliata) mating, footage taken at night using thermal camera technology, Santa Rosa National Park, Costa Rica.

Mick Jenner / Pair of Great crested grebes (Podiceps cristatus) courting, West Sussex, England, UK, March.

Mick Jenner / Pair of Northern gannets (Morus bassanus) courting, Bempton Cliffs RSBP Reserve, Yorkshire, England, UK, June.

Ammonite / Pair of Red-eyed damselflies (Erythromma najas) in tandem, Hickling Broad NWT reserve, Norfolk, England, UK, June.

Ammonite / Pair of Red-eyed damselflies (Erythromma najas) in tandem pulled underwater by surface tension whilst laying eggs beneath the surface of a pond, Hickling Broad NWT reserve, Norfolk, England, UK, June.

Ammonite / Pair of Red-eyed damselflies (Erythromma najas) in tandem laying eggs beneath the surface of a pond, Hickling Broad NWT reserve, Norfolk, England, UK, June.

Ammonite / Several pairs of Red-eyed damselflies (Erythromma najas) in tandem flying above and settling on a pond to lay eggs beneath the surface, Hickling Broad NWT reserve, Norfolk, England, UK, June.

Ammonite / Several pairs of Red-eyed damselflies (Erythromma najas) in tandem flying above and settling on a pond to lay eggs beneath the surface, Hickling Broad NWT reserve, Norfolk, England, UK, June.

Ammonite / Several pairs of Red-eyed damselflies (Erythromma najas) in tandem flying above and settling on a pond to lay eggs beneath the surface, Hickling Broad NWT reserve, Norfolk, England, UK, June.

Ramon Navarro / Male Spanish ibex (Capra pyrenaica) displaying to females on mountain side, Torcal de Antequera Nature Reserve, Malaga, Spain, October.

Ramon Navarro / Pair of Whiskered terns (Chlydonias hybrida) at nest with chicks, with one chick eating a frog, Donana National Park, Seville, Spain, August.

Ramon Navarro / Pair of Whiskered terns (Chlydonias hybrida) at nest with chicks, Donana National Park, Seville, Spain, August.

Ammonite / Pair of Sri Lankan leopards (Panthera pardus kotiya) mating on road, footage taken at night using starlight camera technology, Yala National Park, Sri Lanka.

Ammonite / Pair of Sri Lankan leopards (Panthera pardus kotiya) mating on road, footage taken at night using starlight camera technology, Yala National Park, Sri Lanka.

Ammonite / Pair of Sri Lankan leopards (Panthera pardus kotiya) mating on road, footage taken at night using thermal camera technology, Yala National Park, Sri Lanka.

Ammonite / Pair of Sri Lankan leopards (Panthera pardus kotiya) mating on road, footage taken at night using starlight camera technology, Yala National Park, Sri Lanka.

Ammonite / Pair of Sri Lankan leopards (Panthera pardus kotiya) mating on road, footage taken at night using starlight camera technology, Yala National Park, Sri Lanka.

Mark Hamblin / 2020VISION / Pair of Jackdaws (Corvus monedula) preening on branch near nest hole, Inverness-shire, Scotland, UK, April.

Kristel Richard / A traditionally dressed couple drivings a Friesian mare and a Friesian stallion, harnessed to a phaeton, on the Avenue Louis XIV of the Haras Du Pin, France's oldest national stud, at Le Pin-au-Haras,...

Denis-Huot / Ostrich (Struthio camelus) couple displaying, Masai-Mara Game Reserve, Kenya

Laurent Geslin / Northern gannet pair nesting with chick {Morus bassanus} Brittany, France

Eric Baccega / Couple of common hamster (Cricetus cricetus) mating at the Association 'Sauvegarde Faune Sauvage d'Alsace' (Preserving the wildlife of Alsace) breeding center, Alsace, France, April 2013

Eric Baccega / Couple of common hamster (Cricetus cricetus) interacting during breeding season in a captive breeding program, at the Association 'Sauvegarde Faune Sauvage d'Alsace' (Preserving the wildlife of Alsace...

Eric Baccega / Male and female Grizzly bear courtship (Ursus arctos horribilis) Khutzeymateen Grizzly Bear Sanctuary, British Columbia, Canada, June.

Wild Wonders of Europe / Widstrand / Nine spotted moth (Amata phegea) mating on flower head, North Velebit National Park, Velebit Nature Park, Rewilding Europe area, Velebit mountains, Croatia

Wild Wonders of Europe / Widstrand / Nine spotted moth (Amata phegea) mating on flower head, North Velebit National Park, Velebit Nature Park, Rewilding Europe area, Velebit mountains, Croatia

David Pattyn / Black necked grebe (Podiceps nigricollis) pair performs a dance after mating in which they mimick each other's movements, La Dombes lake area, France, April

XI ZHINONG / Tibetan antelope (Pantholops hodgsoni) male with female, grazing, Kekexili, Qinghai, Tibetan Plateau, China, December

Doug Wechsler / Mating pair of Large milkweed bugs (Oncopeltus fasciatus) on Common milkweed (Asclepias syriaca) leaf, Pennsylvania, USA, July.

Alex Hyde / Man and woman walking along track, rear view, above Monsal Dale near Brushfield, Peak District National Park, Derbyshire, UK. August 2012

Bryan and Cherry Alexander / Selkup couple, Andrey Kargochev and his wife, Ludmilla, about to go berry picking by boat in the autumn, Tolka, Krasnoselkup, Yamal, Western Siberia, Russia

Marie Read / American Cliff Swallows (Petrochelidon pyrrhonota) forced copulation attempt at muddy puddle where they are gathering mud as nesting material. Mono Lake Basin, California, USA, June.

Marie Read / American Cliff Swallows (Petrochelidon pyrrhonota) forced copulation (attempt at muddy puddle where they are gathering mud as nesting material. Mono Lake Basin, California, USA, June.

Marie Read / American Cliff Swallows (Petrochelidon pyrrhonota) forced copulation attempt at muddy puddle where they are gathering mud as nesting material. Mono Lake Basin, California, USA, June.

Mike Potts / Male Wire-crested thorntail (Discosura popelairii) displaying to a female, Wild Sumaco, Ecuador.

Christophe Courteau / Pair of Common / Crested Caracara (Caracara plancus) in tree, Pantanal, Brazil.

Loic Poidevin / Aldabra giant tortoise (Geochelone gigantea) pair mating, Curieuse Marine National Park, Seychelles, Indian Ocean

Loic Poidevin / Aldabra giant tortoise (Geochelone gigantea) pair mating, Curieuse Marine National Park, Seychelles, Indian Ocean

Jeff Rotman / Wolf eels (Anarrichthys ocellatus) male and female pair, Queen Charlotte Strait, British Columbia, Canada, North Pacific Ocean.

Tui De Roy / Volcan Alcedo giant tortoises (Chelonoidis nigra vandenburghi) mating pair, Isabela island, Galapagos

Tui De Roy / Volcan Alcedo giant tortoises (Chelonoidis nigra vandenburghi) mating pair, Isabela island, Galapagos

Solvin Zankl / Banded Demoiselle (Calopteryx splendens) male gripping female while female is laying eggs underwater river, North Germany

LYNN M. STONE / Royal Terns (Thalasseus maximus) stepping toward and then around each other in courtship ritual. Gulf of Mexico beach, St. Petersburg, Florida, USA, April.

LYNN M. STONE / Royal Terns (Thalasseus maximus) in breeding plumage performing courtship behavior. Gulf of Mexico beach, St. Petersburg, Florida, USA, April.

LYNN M. STONE / Royal Tern (Thalasseus maximus) in breeding plumage, in flight with Scaled Sardine 'offering' for female, as part of courtship. Gulf of Mexico beach, Pinellas County, Florida, USA, April.

LYNN M. STONE / Roseate Spoonbills (Platalea ajaja) male climbing onto female's back to attempt mating by new nest (under construction) in Bald Cypress tree. St. John's County, Florida, USA, March.

LYNN M. STONE / Roseate Spoonbills (Platalea ajaja) male climbing onto female's back to attempt mating by new nest (under construction) in Bald Cypress tree. St. John's County, Florida, USA, March.

LYNN M. STONE / Nesting pair of Roseate Spoonbills (Platalea ajaja) in greeting ritual, marked by bill touching and vocalizations, by new nest (under construction) in Bald Cypress tree. St. John's County, Florida, US...

LYNN M. STONE / Nesting pair of Roseate Spoonbills (Platalea ajaja) in greeting ritual, marked by bill touching and vocalizations, by new nest (under construction) in Bald Cypress tree. St. John's County, Florida, US...

LYNN M. STONE / Great Egrets (Ardea alba) preening their breeding plumage, at nest. Osceola County, Florida, USA, March.

LYNN M. STONE / Royal Tern (Thalasseus maximus) in breeding plumage, with Scaled Sardine 'offering' to a female as part of courtship. Black Skimmers are in the background. Pinellas County, Florida, USA, April.