George McCarthy / RF- Tawny owl with moon behind (Strix aluco), UK. (This image may be licensed either as rights managed or royalty free.)

Jack Dykinga / Burrowing owl (Athene cunicularia) female and ten chicks aged a few weeks. Marana, Arizona, USA. May.

Sven Zacek / Ural owl (Strix uralensis) hunting, Tartumaa county, Southern Estonia.

Sven Zacek / Ural owl (Strix uralensis) in flight, hunting, Tartumaa county, Southern Estonia. February.

Sven Zacek / Ural owl (Strix uralensis) nestling, Tartumaa county, Southern Estonia. May.

John Chan / Great horned owl (Bubo virginianus) chicks stretching and flapping their wings, Southern California, USA, May.

John Chan / Great horned owl (Bubo virginianus) chick watching for parents to return with food, Southern California, USA, June.

John Shaw / Western screech owl (Megascops kennicottii) is camouflaged as it looks from a tree cavity. Bosque del Apache National Wildlife Refuge, New Mexico, USA, January.

Jack Dykinga / Burrowing owls (Athene cunicularia) one moving its head - with blurred motion. Marana, Arizona, USA, November.

John Cancalosi / Great horned owl (Bubo virginianus) chick stretching its wings in nest in a Saguaro (Carnegiea gigantea), is groomed by its parent, Sonoran Desert, Arizona, USA, May.

Bernard Castelein / Spotted owlet ( Athena brama), Keoladeo NP, Bharatpur, India

Marie Read / Snowy Owl (Nyctea scandiaca) female perched, Amherst Island, Ontario, Canada, January.

Markus Varesvuo / Pygmy owl (Glaucidium passerinum) perched in lichen covered tree. Helsinki, Finland. February.

Karine Aigner / Cuban bare-legged owl (Margarobyas lawrencii) perched, Cienaga de Zapata, Cuba.

Karine Aigner / Cuban bare-legged owl (Margarobyas lawrencii) in nest hole. Cienaga de Zapata, Cuba.

Sven Zacek / Eurasian pygmy owl (Glaucidium passerinum) perched on snow covered branch in evening light. Vorumaa, Southern Estonia. November.

Sven Zacek / Ural owl (Strix uralensis) female on nest, male landing with twig in beak. Tartumaa, Southern Estonia. April.

Sven Zacek / Ural owl (Strix uralensis) male presenting prey to nesting mate. Tartumaa, Southern Estonia. April.

Sven Zacek / Ural owl (Strix uralensis) female feeding at nest on rodent prey presented by mate. Tartumaa, Southern Estonia. April.

Sven Zacek / Ural owl (Strix uralensis) female on the nest with nestling hidden under wing. Tartumaa, Southern Estonia. April.

Sven Zacek / Ural owl (Strix uralensis) female stretching wings whilst perched in Spruce (Picea sp) tree. Tartumaa, Southern Estonia. May.

Sven Zacek / Ural owl (Strix uralensis) female and nestling on nest in tree stump. Tartumaa, Southern Estonia. May.

Sven Zacek / Ural owl (Strix uralensis) female on nest after snowfall. Tartumaa, Southern Estonia. March.

Sven Zacek / Ural owl (Strix uralensis) female on nest in tree stump. Tartumaa, Southern Estonia. April.

Sven Zacek / Ural owl (Strix uralensis) female in flight having taken off from nest, in evening light. Tartumaa, Southern Estonia. May.

Sven Zacek / Ural owl (Strix uralensis) female flying with prey in beak. Flying back to nest in evening light. Tartumaa, Southern Estonia. May.

Sven Zacek / Ural owl (Strix uralensis) perched on Alder (Alnus sp) tree at dusk. Tartumaa, Southern Estonia. April.

Pedro Narra / Little owl (Athene noctua) Sado Estuary, Portugal. June

Jack Dykinga / Burrowing owl (Athene cunicularia) at sunset, standing on one leg, Marana, Sonoran Desert, Arizona, USA. October.

Jack Dykinga / Burrowing owl (Athene cunicularia) with head turned to one side, Marana, Sonoran Desert, Arizona, USA. October.

Ann & Steve Toon / Spotted eagle owl (Bubo africanus) subadult at nigh by water, Zimanga private game reserve, KwaZulu-Natal, South Africa, September

Jack Dykinga / Burrowing owl (Athene cunicularia), two huddled together. Marana, Pima County, Arizona, USA.

David Allemand / Snowy owl (Bubo scandiacus) female landing in the snow, Quebec, Canada, March.

David Allemand / Snowy owl (Bubo scandiacus) Female landing in the snow, Quebec, Canada

Felis Images / Spotted owlets (Athene brama) group of juveniles, Tamil Nadu, India.

Dave Bevan / Slow motion clip of a Tawny owl (Strix aluco) leaving nest site in hollow tree, Carmarthenshire, Wales, UK, April.

Guy Edwardes / Snowy owl (Bubo scandiacus) walking on ground in snow, one foot raised, Ontario, Canada, January.

Markus Varesvuo / Snowy owl (Bubo scandiaca) female face close up, Canada February

Markus Varesvuo / Snowy owl (Bubo scandiaca) female sitting among snow covered vegetation on ground, Canada February

Markus Varesvuo / Hawk owl (Surnia ulula) takingn off from powder snow, possibly with prey in talons, Kuusamo Finland February

Sven Zacek / Great grey owl (Strix nebulosa) perched on dead umbellifer plant, winter, Finland, February.

Markus Varesvuo / Snowy owl (Bubo scandiaca) female, with lights behind, Canada, February.

Neil Aldridge / Portrait of an adult Spotted eagle owl (Bubo africanus) Table Mountain National Park, South Africa.

Bence Mate / Two Burrowing owls (Athene cunicularia) fledgling with adult about to take off, Pantanal, Brazil.

Bence Mate / Burrowing owl (Athene cunicularia) fledgling with head on side, Pantanal, Brazil. November.

Michel Poinsignon / Eurasian pygmy Owl (Glaucidium passerinum) perched on conifer branch, Vosges Mountains, France, June.

Wim van den Heever / Pearl-Spotted Owl (Glaucidium perlatum) perched on a branch. Okavango Delta Botswana

Ben Hall / Eagle owl (Bubo bubo) in flight through forest, backlit at dawn, Czech Republic, November. Captive.

Ben Hall / Eurasian eagle owl (Bubo bubo) flying low over snow covered grouns with trees in background, Czech Republic, February. Captive.

Gerrit Vyn / Great horned owls (Bubo virginianus) roosting in an abandoned barn. Idaho, USA. February.

Gerrit Vyn / Snowy Owl (Bubo scandiacus) fluffing feathers, this image was taken during a massive increase in the range and population of snowy owls. Boundary Bay, Canada. March.

Sven Zacek / Ural owl (Strix uralensis) perching on an Apsen tree during the blue hour of dawn, Tartumaa, Estonia, April.

Sven Zacek / Low angle shot of Ural owl (Strix uralensis) female returning to its nest at night. Southern Estonia, May.

Sven Zacek / Ural owl (Strix uralensis) chick trying to climb an aspen tree with its beak, talons and wings, Southern Estonia. June.

Sven Zacek / Ural owl (Strix uralensis) chick trying to climb an aspen tree with its beak, talons and wings, Southern Estonia. June.

Sven Zacek / Ural owl (Strix uralensis) female feeding her young with part of a pellet it has regurgitated. Estonia, May.

Sven Zacek / Female Ural owl (Strix uralensis) flying over a clear-cut area, Southern Estonia, May.

Sven Zacek / Male Ural owl (Strix uralensis) flying to nest to feed female, Southern Estonia, March.

George Sanker / Barred owl (Strix varia) stretching wings, Corkscrew Swamp Audubon Sanctuary, Florida, USA, March.

Jack Dykinga / Great horned owl (Bubo virginianus) chicks in nest in Saguaro cactus (Carnegiea gigantea) at sunset, Santa Catalina Mountains, Arizona, USA, May.

Jack Dykinga / Great horned owl (Bubo virginianus) chicks nesting in saguaro cactus (Carnegiea gigantea), near Oracle, Sonoran Desert, Arizona, USA, May.

Jack Dykinga / Great horned owl (Bubo virginianus) chick nesting in Saguaro cactus (Carnegiea gigantea), Santa Catalina Mountains, Arizona, USA, May.

Todd Mintz / Great horned owlet (Bubo virginianus) talons Regina, Saskatchewan, Canada. June 2013.

Ole Jorgen Liodden / Eurasian eagle-owl (Bubo bubo) in flight, Norway, July.

Ole Jorgen Liodden / Great grey owl (Strix nebulosa lapponica) in flight, close up, Finland, March.

Ole Jorgen Liodden / Great grey owl (Strix nebulosa lapponica) hunting in flight, Lapland, Finland, March.

Markus Varesvuo / Pharaoh eagle owl (Bubo ascalaphus) on sand, Morocco, March.

Jussi Murtosaari / Snowy owl (Bubo scandiacus) Alajarvi, Etela-Pohjanmaa / Southern Ostrobothnia, Finland

Andy Rouse / Little owl (Athene noctua) on old wheel, UK, April.

Michel Poinsignon / Two tawny owl (Strix aluco) chicks emerging from nest in tree, Luxembourg. May.

Markus Varesvuo / Blakiston's Fish Owl (Ketupa blakistoni) perched, Hokkaido, Japan, February.

Sven Zacek / Ural owl (Strix uralensis) flying to nest with star trails in sky above, Estonia, May. Winner of the Birds category in the Melvita Nature Images Awards competition 2014.

Bence Mate / Long eared owl (Asio otus) chicks perched on a cross, with the moon, in the background, Puszatszer, Hungary, June.

Jussi Murtosaari / Great Grey Owl (Strix nebulosa) diving for prey, southern Finland, April.

Eric Medard / Little owl (Athene noctua) on water pump in garden, taken at night with infra red remote camera trap, Mayenne, Pays de Loire, France.

Pascal Tordeux / Boy feeding a Little owl (Athene noctua) chick hit by a car, France, May 2013. Model released.

Roger Powell / Little owl (Athene noctua) perched on a fence post, stretching its wings, Castro Verde, Alentejo, Portugal, April.

Roger Powell / Little owl (Athene noctua) perched on a fence post, ruffling its feathers, Castro Verde, Alentejo, Portugal, April.

Markus Varesvuo / Tengmalm's Owl (Aegolius funereus) close-up of eye. Kuusamo Finland, May. Winner of the Birds Category in the Finnish Nature Photo of the Year Competition 2013

Loic Poidevin,Loic Poidevin / Short-eared Owl (Asio flammeus) diving at prey, Breton Marsh, West France, April

Sven Zacek / Tawny owl (Strix aluco) peering out of its nest hole in tree, Southern Estonia, February.

Sven Zacek / Female Long-eared owl (Asio otus) peeking from behind a spruce tree, Southern Estonia, June.

Milan Radisics / Long-eared Owls (Asio otus) roosting in tree, Szeged city, Southern Hungary, February 2009

Ben Hall / Eurasian Eagle owl (Bubo bubo) in flight through dense forest, Czech Republic, January

Danny Green / Great Grey owl (Strix nebulosa) taking off from the ground in snow, Finland, April. Bookplate from Danny Green's 'The Long Journey North'

Andy Trowbridge / RF- Great Grey Owl (Strix nebulosa) adult and chicks on nest. Nest 'frame' is manmade. Ostersund, Sweden. June. (This image may be licensed either as rights managed or royalty free.)

Doug Gimesy / Jacky Hunt, specialist in bird rescue and rehabilitation, with two Boobook owls (Ninox boobook), which she is providing temporary accommodation for in her factory. These birds were evacuated from the...

Doug Gimesy / Jacky Hunt, a specialist in bird rescue and rehabilitation, with two Boobook owls (Ninox boobook), which she is providing temporary accommodation for in her factory. These birds were evacuated from th...

Oscar Dewhurst / Brown wood-owl (Strix leptogrammica) perched on branch at night. Goa, India. September.

Hanne & Jens Eriksen / Great horned owl (Bubo virginianus) in flight. Saskatchewan, Canada, August.

Ann & Steve Toon / Spotted eagle owl (Bubo africanus) at nest box, Paternoster, Western Cape, South Africa.

Jack Dykinga / Burrowing owl (Athene cunicularia) curious juvenile cocking head at 90 degrees. Sheltering in shade of Corn / Maize crop. Marana, Arizona, USA.

Dong Lei / Little owl (Athene noctua) perched on Mani stones. Sanjiangyuan National Nature Reserve, Qinghai Province, Qinghai-Tibet Plateau. October.

Karine Aigner / Great horned owl (Bubo virginianus) owlet in tree. Texas, USA. April.

Karine Aigner / Great horned owl (Bubo virginianus) owlet in tree. Texas, USA. April.

Tony Heald / Black-banded owl (Strix huhula), portrait. Bird of Prey Centre, UK. Captive.