Anup Shah / Lesser flamingos {Phoeniconaias minor} performing 'wing salute' as part of courtship display, the wings are spread out to the side of the body and held in this position for several seconds, making the...

Martin Willis / Victoria's Riflebird (Ptiloris victoriae) male in courtship display, Atherton Tableland, Queensland, Australia. Sequence 2 of 3

John Chan / Crenulated fiddler crab (Uca crenulata) waving its major claw at another crab, part of a courtship display, Southern California, USA, June.

John Shaw / Great frigatebird (Fregata minor) male at nest site, with gular sac inflated to attract females. Genovesa Island, Galapagos, May.

Bernard Castelein / Sarus crane (Grus antigone), male displaying, Keoladeo NP, Bharatpur, India

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.

Russell Cooper / Mandarin duck drake (Aix galericulata) on the water, showing orange 'sail' feathers which are used when displaying, Southwest London, UK, March.

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.

John Chan / Elegant terns (Thalasseus elegans) courting, Southern California, USA, March.

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.