Tony Wu / Bowhead whale (Balaena mysticetus), group socialising in shallow water, aerial view. Part of larger group of more than 50 whales congregating, Sea of Okhotsk sub-population, Russia.

Sandesh Kadur / Slow motion clip of Amur falcons (Falco amurensis) congregating at roost site during their migration from Siberia to Africa, near Doyang reservoir, Nagaland, India, October.

Sandesh Kadur / Amur falcons (Falco amurensis) congregating during their migration from Siberia to Africa, near Doyang reservoir, Nagaland, India, October.

Sandesh Kadur / Amur falcons (Falco amurensis) congregating during their migration from Siberia to Africa, near Doyang reservoir, Nagaland, India, October.

Philippe Clement / Flock of Jackdaws (Corvus monedula) congregating at dusk at communal roost, Belgium, December.

Cyril Ruoso / South american sea lion (Otaria byronia) and American fur seal (Arctocephalus australis) hauled out on the shore of Punta Coles Reserve, Peru.

Juan Carlos Munoz / Lesser flamingos (Phoeniconaias minor) on Lake Bogoria, Kenya

Solvin Zankl / Just three hours after they hatch from the water and moult into mature adults, the male Long-tailed / Tisza mayfly (Palingenia longicauda) perish. Adult mayflies have no mouth opening and no guts. The...

Yva Momatiuk & John Eastcott / Sandhill Crane (Grus canadensis) flocks congregating before flying south in autumn, Denali National Park and Preserve, Alaska

David Tipling / Blacktip reef shark (Carcharhinus melanopterus) group congregating to feed at night. Ghizo, New Georgia Islands, Western Province, Solomon Islands.

Sandesh Kadur / Huge flock of Amur falcons (Falco amurensis) congregating at a roosting site during their migration from Siberia to Africa, Doyang Reservoir, Nagaland, India, October.

Sandesh Kadur / Amur falcons (Falco amurensis) congregating during their migration from Siberia to Africa, near Doyang reservoir, Nagaland, India, October.