Guy Edwardes / Barn owl (Tyto alba) in flight above post and wildflowers, in morning light. The Hawk Conservancy Trust, Hampshire, England, UK. July. Captive.

Michael Quinton / Northern Hawk Owl (Surnia ulula) pair at nest, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) peering from nest, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) parent with chicks at nest, Alaska

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

Markus Varesvuo / Hawk Owl perched in frost (Surnia ulula) Finland

Markus Varesvuo / Hawk owl (Surnia ulula) juvenile, portrait, Kuusamo, Finland, May

Markus Varesvuo / Hawk owl (Surnia ulula) perched on branch calling, Kuusamo, Finland, May

Markus Varesvuo / Hawk Owl (Surnia ulula) perched on snowy tree in front of the moon. Kuusamo, Finland, February.

Floris van Breugel / Burrowing Owl (Athene cunicularia) standing at entrance to burrow, and watching a Red-tailed Hawk circling above. Salton Sea, California, USA.

Michael Quinton / Northern Hawk Owl (Surnia ulula) baby perching on branch, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) perching on branch during snowfall in spring, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) at nest with chicks, Alaska

Loic Poidevin / Northern hawk-owl (Surnia ulula) looking down from nest. Finland. May.

Cyril Ruoso / White-browed hawk owl (Ninox superciliaris) perched in tree. Berenty Reserve, Madagascar.

Oscar Dewhurst / Long-eared owl (Asio otus) in flight over farmland. Durham, UK. May

Oscar Dewhurst / Long-eared owl (Asio otus) in flight over farmland. Durham, UK. May

Markus Varesvuo / Hawk owl (Surnia ulula), looking at camera with head turned 180 degrees, perched on branch. Helsinki, Finland. November.

Markus Varesvuo / Hawk owl (Surnia ulula) and Black woodpecker (Dryocopus martius) perched in tree. Helsinki, Finland. December. Small repro only.

Sven Zacek / Hawk owl (Surnia ulula) perched on Oak (Quercus sp) branch. Tartumaa, Southern Estonia. November.

Michael Quinton / Northern Hawk Owl (Surnia ulula), Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula), Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) on nest, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) chicks in nest, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) chicks in nest, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) parent with chicks at nest, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) brooding chick on nest, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) on nest, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) with Northern Red-backed Vole (Clethrionomys rutilus) prey, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) with Northern Red-backed Vole (Clethrionomys rutilus) prey, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) male bringing Northern Red-backed Vole (Clethrionomys rutilus) prey to incubating female, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) in nest in taiga, Alaska

Michael Quinton / Northern Hawk Owl (Surnia ulula) pair at nest, Alaska

Markus Varesvuo / Hawk Owl (Surnia ulula) portrait, Helsinki, Finland, December.

Markus Varesvuo / Hawk Owl (Surnia ulula) regurgitating pellet before eating vole prey, Helsinki, Finland, December.

Alan Murphy/ BIA / Northern Hawk Owl (Surnia ulula) hunting, Minnesota

Alan Murphy/ BIA / Northern Hawk Owl (Surnia ulula), Minnesota

Werner Oppermann/ BIA / Northern Hawk Owl (Surnia ulula), Saxony, Germany

Jussi Murtosaari / Northern hawk-owl (Surnia ulula) Finland, January.

Jussi Murtosaari / Northern hawk-owl (Surnia ulula) taking off, Finland

Jussi Murtosaari / Northern hawk-owl (Surnia ulula) perched, Finland, January.

Jussi Murtosaari / Northern hawk-owl (Surnia ulula) perched with the moon, Finland, January.

Jussi Murtosaari / Northern hawk-owl (Surnia ulula), perched, Finland, January.

Jussi Murtosaari / Northern hawk-owl (Surnia ulula) perched, Finland, January.

Sylvain Cordier / Northern hawk owl (Surnia ulula) perched, Nome, Alaska, USA, March.

Gerrit Vyn / Northern Hawk Owl (Surnia ulula) preening, Varanger, Norway. June.

Gerrit Vyn / Northern Hawk Owl (Surnia ulula). Varanger, Norway. June.

Gerrit Vyn / Northern Hawk Owl (Surnia ulula). Varanger, Norway. June.

Gerrit Vyn / Northern Hawk Owl (Surnia ulula). Varanger, Norway. June.

Gerrit Vyn / Fledgling Northern Hawk Owl (Surnia ulula). Finland. June.

Gerrit Vyn / Fledgling Northern Hawk Owl (Surnia ulula). Finland. June.

Steve Gettle / Northern Hawk Owl (Surnia ulula), northern Michigan

Steve Gettle / Northern Hawk Owl (Surnia ulula), northern Michigan

Steve Gettle / Northern Hawk Owl (Surnia ulula), northern Michigan

Markus Varesvuo / Hawk owl (Surnia ulula) landing in snow, Kuusamo Finland February

Markus Varesvuo / Hawk owl (Surnia ulula) two perched on top of conifer tree, Kuusamo Finland February

Markus Varesvuo / Hawk owl (Surnia ulula) flying portrait, Kuusamo Finland February

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

Markus Varesvuo / Hawk owl (Surnia ulula) flying low over ground, Kuusamo Finland February

Markus Varesvuo / Hawk owl (Surnia ulula) looking intently at the ground, could be able to swoop on prey, Kuusamo Finland February

Markus Varesvuo / Hawk owl (Surnia ulula) looking intently at the ground, could be able to swoop on prey, Kuusamo Finland February

Markus Varesvuo / Hawk owl (Surnia ulula) flying low over ground, Kuusamo Finland February

Andres M. Dominguez / Hawk Owl (Surnia ulula) diving prey below the snow, Finland, March.

Andres M. Dominguez / Hawk Owl (Surnia ulula) perched in a pine, Finland, March.

Nick Upton / Graham Guest at the top of a ladder checking a nestbox for Kestrel chicks (Falco tinnunculus) during a survey for the Hawk and Owl Trust's Kestrel Highways project, Congresbury, Somerset, UK, June. Mo...

Nick Upton / Kestrel chick (Falco tinnunculus) having its developing primary feathers measured during a nestbox survey for the Hawk and Owl Trust's Kestrel Highways project, Congresbury, Somerset, UK, June. Model...

Nick Upton / Colin Morris weighing a Kestrel chick( Falco tinnunculus) in a bag during a nestbox survey for the the Hawk and Owl Trust's Kestrel Highways project, Congresbury, Somerset, UK, June. Model released.

Nick Upton / Four Kestrel chicks (Falco tinnunculus) in a nestbox, one with a mouse in its beak, found during a survey for the Hawk and Owl Trust's Kestrel Highways project, Congresbury, Somerset, UK, June.

Nick Upton / Colon Morris ringing a Kestrel chick (Falco tinnunculus) found during a nestbox survey for the the Hawk and Owl Trust's Kestrel Highways project, Congresbury, Somerset, UK, June. Model released.

Nick Upton / Kestrel chick (Falco tinnunculus) being ringed after being found during a nestbox survey for the the Hawk and Owl Trust's Kestrel Highways project, Congresbury, Somerset, UK, June. Model released.

Nick Upton / Kestrel chick (Falco tinnunculus) being ringed after being found during a nestbox survey for the the Hawk and Owl Trust's Kestrel Highways project, Congresbury, Somerset, UK, June. Model released.

Nick Upton / Graham Guest at the top of a ladder held by Barry Gray putting a Kestrel chick (Falco tinnunculus) back into a nestbox during a survey for the Hawk and Owl Trust's Kestrel Highways project, Congresbur...

Nick Upton / Graham Guest at the top of a ladder removing a Kestrel chick (Falco tinnunculus) from a nestbox for ringing and measuring during a survey for the Hawk and Owl Trust's Kestrel Highways project, Congres...

Nick Upton / Colin Morris takes a Kestrel chick (Falco tinnunculus) for ringing from a bag held by Keith Lapham as Barry Gray and Graham Guest look on during a nestbox survey for the the Hawk and Owl Trust's Kest...

Nick Upton / Kestrel chick (Falco tinnunculus) held after being ringed during a nestbox survey for the the Hawk and Owl Trust's Kestrel Highways project, Congresbury, Somerset, UK, June. Model released.

Melvin Grey / Northern hawk owl (Surnia ulula) adult plucking prey on post, Churchill, Manitoba, Canada, June.

Melvin Grey / Northern hawk owl (Surnia ulula) adult at nest with young, Churchill, Manitoba, Canada, June.

Danny Green / Hawk Owl (Surnia ulula) perched in a pine, Finland, June.

Danny Green / Hawk Owl perched (Surnia ulula), Finland, June.

Danny Green / Hawk Owl young (Surnia ulula), Finland, June.

Sean Crane / Short-eared Owl (Asio flammeus) fighting with Northern Harrier (Circus cyaneus) male over vole prey, British Columbia, Canada

Ole Jorgen Liodden / Northern hawk owl (Surnia ulula ulula) hunting, swooping low to the snow, Norway, February.

Ole Jorgen Liodden / Northern hawk owl (Surnia ulula ulula) in flight during snowfall, Tana, Norway, April.

Ole Jorgen Liodden / Northern hawk owl (Surnia ulula) flying through snowy forest, Finnmark, Norway. April.

Erlend Haarberg / Northern hawk owl (Surnia ulula) perched in birch forest, Sarek National Park, Laponia World Heritage Site, Lapland, Sweden, August.

Erlend Haarberg / Northern hawk owl (Surnia ulula) perched in birch forest, Sarek National Park, Laponia World Heritage Site, Lapland, Sweden, August.

Erlend Haarberg / Northern hawk owl (Surnia ulula) perched in birch forest, Sarek National Park, Laponia World Heritage Site, Lapland, Sweden, August.

Hanne & Jens Eriksen / Brown hawk owl (Ninox scutulata) pair on branch, India, January.

Jussi Murtosaari / Northern hawk-owl (Surnia ulula) Jyvaskya, Keski-Suomi, Lansi- ja Sisa-Suomi / Central and Western Finland, Finland. January

Alan Murphy / Northern Hawk Owl (Surnia ulula), Minnesota

Markus Varesvuo / Hawk owl (Surnia ulula) perched, Liminka Finland, December

Markus Varesvuo / Hawk Owl (Surnia ulula) in flight with lemming prey. Vaala, Finland. March

Markus Varesvuo / Hawk owl (Surnia ulula) perched on tree branch with lemming prey. Helsinki, Finland. Magic Moments book plate.

Markus Varesvuo / Hawk owl (Surnia ulula) hunting lemmings in the snow. Liminka, Finland.

Markus Varesvuo / Hawk Owl perched (Surnia ulula) Finland