Loic Poidevin / Northern ravens (Corvus corax) interacting in snow, Leon, Spain, February.

Philippe Clement / Territorial Common raven (Corvus corax) on cliff top, tearing out vegetation, Eshaness, Northmavine, Shetland Islands, Scotland, UK, May.

Philippe Clement / Common raven (Corvus corax) taking off from the top of a sea cliff, Eshaness, Northmavine, Shetland Islands, Scotland, UK, May.

Philippe Clement / Common raven (Corvus corax) calling from top of sea cliff, Eshaness, Northmavine, Shetland Islands, Scotland, UK, May.

Dave Bevan / Common raven (Corvus corax) flying to nest to feed fledglings, Carmarthenshire, Wales, UK, May.

Mark Hamblin / Raven (Corvus corax) adult calling from rock in mountain habitat, Scotland, UK. November. Third place in British Birds Bird Photograph of the Year competition 2016.

Staffan Widstrand / Raven (Corvus corax) mobbing Gyrfalcon (Falco rusticolus), Hornoya Island, Varanger Peninsula, Norway, March.

Sven Zacek / Ravens (Corvus corax) fighting in bog during snowfall, Tartumaa, Estonia. December.

Espen Bergersen / Common raven (Corvus corax) pair in courtship display, flying upsidedown and calling, Hornoya bird cliff, Norway. March.

Espen Bergersen / Gyrfalcon (Falco rusticolus) and Raven (Corvus corax) in flight, Hornoya bird cliff, Finnmark, Norway. March

Markus Varesvuo,Markus Varesvuo / Pair of Common ravens (Corvus corax) displaying, Vardo, Norway, March.

Markus Varesvuo,Markus Varesvuo / Commen raven (Corvus corax) flying in falling snow, Vardo, Norway, March.