Tim Fitzharris / Great Horned Owl (Bubo virginianus) in its pale form perching on snag, British Columbia, Canada

Tim Fitzharris / Great Horned Owl (Bubo virginianus) pale form, perched in tree, Alberta, Canada

LYNN M. STONE / Great horned owl {Bubo virginianus}, Alaska, US Captive.

LYNN M. STONE / Great horned owl portrait {Bubo virginianus} Alaska, USA Captive.

LYNN M. STONE / Great horned owl {Bubo virginianus} Alaska, US Captive.

Geoff Simpson / Great horned owl portrait {Bubo virginianus}

John Cancalosi / Great horned owl {Bubo virginianus} on nest with young in saguaro cactus, Arizona, USA

LYNN M. STONE / Great horned owl (Bubo virginianus), juveniles at nest. USA Captive.

Tom Vezo / Great horned owl portrait. Raptor Center, New York. Captive bird

Tom Vezo / Great horned owl (Bubo virginianus) portrait. (C) Raptor Center, New York

Tom Vezo / Great horned owl (Bubo virginianus). Raptor Center, New York, USA

John Cancalosi / Great horned owl (Bubo virginianus) adult with chick in nest Arizona, USA Sonoran Desert. Nest in Saguaro cactus

John Cancalosi / Great horned owl (Bubo virginianus), adult & young in nest Arizona, USA Sonoran Desert. Nest in Saguaro cactus

John Cancalosi / Great horned owl (Bubo virginianus) adult with chicks in nest Arizona, USA Sonoran Desert. Nest in saguaro cactus

John Cancalosi / Great horned owl (Bubo virginianus), young in nest Arizona, USA Sonoran Desert. Nest in Saguaro cactus

John Cancalosi / Great horned owls (Bubo virginianus), young in nest, Arizona, USA Sonoran Desert. Nest in Saguaro cactus

John Cancalosi / Great horned owl young in nest in Sagauro cactus, Sonoran Desert, Arizona, USA

Tom Vezo / Great horned owl, USA

Colin Seddon / Portrait of Great horned owl {Bubo virginianus} showing one nictitating membrane, UK, captive

Sumio Harada / Great Horned Owl (Bubo virginianus) in nest with chicks, Montana

Todd Mintz / Great horned owlet (Bubo virginianus) with mother in nest, Regina, Saskatchewan, Canada, May

Steve Gettle / Great Horned Owl (Bubo virginianus), Howell Nature Center, Michigan

Steve Gettle / Great Horned Owl (Bubo virginianus) in winter, Howell Nature Center, Michigan

Sebastian Kennerknecht / Great Horned Owl (Bubo virginianus) parent with owlets in nest in cliff, Alum Rock Park, San Jose, California

Tim Fitzharris / Great Horned Owl (Bubo virginianus) perched in tree dusted with snow, British Columbia, Canada

Geoff Simpson / Great horned owl {Bubo virginianus} C