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...

Jose B. Ruiz / Shepherds painting red onto underside of male sheep. When he mates with a female she will have a red mark on her fleece, showing that she has been mated. Torres del Paine. Patagonia, Puerto Natales, C...

Marie Read / Black-necked sStilt (Himantopus mexicanus) pair building nest in shallow wetland: male in foreground is squatting and pushing backwards with his feet/legs to form a nest scrape in vegetation the pair...

Marie Read / Black-necked Stilt (Himantopus mexicanus) pair building nest in shallow wetland, male in foreground in squatting and pushing backwards with his feet/legs to form a nest scrape in vegetation the pair...

Marie Read / American avocet (Recurvirostra americana) 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 / American Avocet (Recurvirostra americana), pair copulating, Bear River Migratory Bird Refuge, Utah, USA, May.

Marie Read / Northern cardinal (Cardinalis cardinalis) male (right) feeding his mate in spring as part of courtship/pair formation, termed "allofeeding", New York, USA, May.

Marie Read / Northern cardinal (Cardinalis cardinalis) male (right) feeding his mate in spring as part of courtship/pair formation, termed "allofeeding", New York, USA, May.

Marie Read / Northern cardinal (Cardinalis cardinalis) male (right) feeding his mate in spring as part of courtship/pair formation, termed "allofeeding", New York, USA, May.

Marie Read / Horned puffins (Fratercula corniculata) mated pair 'billing', St. Paul Island, Pribilofs, Alaska, USA, July.

Andy Sands / Long horn beetle (Arhapalus rusticus) smaller male next to larger female under bark of dead pine tree, probably recently mated, Surrey, England, UK. August

Gerrit Vyn / Black scoters (Melanitta nigra) male and female mated pair on a tundra pond. Seward Peninsula, Alaska USA June