Todd Mintz / Great Horned owl, (Bubo virginianus) in flight, Regina, Saskatchewan, Canada, March

ZSSD / Great Horned Owl (Bubo virginianus) portrait, native to North America

Rolf Nussbaumer / Young Great horned owl chick in nest {Bubo virginianus} Rio Grande Valley Texas USA.

Gerry Ellis / Great Horned Owl (Bubo virginianus) close-up portrait, North America

Jim Brandenburg / Great Horned Owl (Bubo virginianus) with rabbit it has captured, Minnesota

Tim Fitzharris / Great Horned Owl (Bubo virginianus), pale form, perching in a snow-covered tree, British Columbia, Canada

Todd Mintz / Great Horned (Bubo virginianus) owlets in nest. Saskatchewan, Canada, February.

Todd Mintz / Great Horned (Bubo virginianus) owlet fledging. Saskatchewan, Canada, May.

Todd Mintz / Great Horned (Bubo virginianus) owlet fledging. Saskatchewan, Canada, May.

Todd Mintz / Great Horned (Bubo virginianus) owlet fledging. Saskatchewan, Canada, May.

Todd Mintz / Great Horned Owlet (Bubo virginianus) fledging. Saskatchewan, Canada

Todd Mintz / Great Horned Owl (Bubo virginianus) in flight, seen from below. Saskatchewan, Canada, May.

Todd Mintz / Great Horned Owl (Bubo virginianus) in flight, seen from below. Saskatchewan, Canada, May.

Todd Mintz / Great Horned Owl (Bubo virginianus) in flight through branches. Saskatchewan, Canada, May.

Todd Mintz / Great Horned Owl (Bubo virginianus) chicks on the nest. Saskatchewan, Canada

Sumio Harada / Great Horned Owl (Bubo virginianus) chicks in nest on power pole, Montana

Floris van Breugel / Great horned Owl (Bubo virginianus) camouflaged against desert rock, Eastern Sierra, California, USA. May

Loic Poidevin / Great horned owl (Bubo virginianus) Pointe Pelee, Ontario, Canada May

Larry Michael / Great Horned Owl (Bubo virginianus) juvenile perched on owl model, Wisconsin, USA

Larry Michael / Great Horned Owl (Bubo virginianus) juvenile perched on owl model, Wisconsin, USA

Tim Fitzharris / Great Horned Owl (Bubo virginianus) pale form, Kootenays, British Columbia, Canada

Todd Mintz / Great horned owl (Bubo virginianus) adult portrait, Saskatchewan, Canada, May

Todd Mintz / Great horned owl (Bubo virginianus) perched in conifer, Saskatchewan, Canada, March

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

Todd Mintz / Great horned owlet (Bubo virginianus) displaying defensive warning, Regina, Saskatchewan, Canada, June

Todd Mintz / Great horned owlet (Bubo virginianus) displaying defensive warning, Regina, Saskatchewan, Canada, June

Todd Mintz / Great horned owlet (Bubo virginianus) displaying defensive warning, Regina, Saskatchewan, Canada, June

Gerrit Vyn / Great Horned owl (Bubo virginianus) chicks in nest, this species does not build its own nest but occupies the nest of another species from a previous season. Okanogan County, Washington, USA April

Todd Mintz / Great Horned owlets (Bubo virginianus) three on ground, Regina, Saskatchewan, Canada, June

Todd Mintz / Great Horned owlets (Bubo virginianus) displaying on ground, Regina, Saskatchewan, Canada, June

Todd Mintz / Great Horned owl (Bubo virginianus) wing detail, Regina, Saskatchewan, Canada

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

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

Steve Gettle / Great Horned Owl (Bubo virginianus), Howell Nature Center, Michigan. Sequence 1 of 2

Steve Gettle / Great Horned Owl (Bubo virginianus), rotating head 180 degrees, Howell Nature Center, Michigan. Sequence 2 of 2

Matthias Breiter / Great Horned Owl (Bubo virginianus) portrait, Haines, Alaska

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

Steve Gettle / Great Horned Owl (Bubo virginianus) during snowstorm, Howell, Michigan

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

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

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

Barry Mansell / Great Horned Owl (Bubo virginianus) juvenile on nest. Everglades National Park, South Florida, USA, April.

Diane McAllister / Great horned owl (Bubo virginianus) taking off from the rooftop of an old barn. Portola, California, USA, August

Diane McAllister / Three Great horned owl chicks (Bubo virginianus) with their beaks open begging for food in their nest in a Cottonwood tree. Suburban northwest Reno, Nevada, USA, April

Sebastian Kennerknecht / Great Horned Owl (Bubo virginianus) roadkill, Iowa

Gerrit Vyn / Pale Great Horned Owl (Bubo virginianus) perched in branch, Cold Lake Provincial Park, Alberta, Canada. May.

Gerrit Vyn / Great Horned Owl (Bubo virginianus) fledgling chick, perched on branch, Cold Lake Provincial Park, Alberta, Canada. May.

Gerrit Vyn / Female Great Horned Owl (Bubo virginianus) on nest. Lawrence County, South Dakota, USA

Donald M. Jones / Great Horned Owl (Bubo virginianus) in cottonwood tree, western Montana

Claudio Contreras / Great horned owl (Bubo virginianus) on nest in cactus, El Vizcaino Biosphere Reserve, Baja California Peninsula, Mexico, March

Suzi Eszterhas / Great Horned Owl (Bubo virginianus) owlet, Pantanal, Brazil

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

Donald M. Jones / Great Horned Owl (Bubo virginianus) owlet winking, western Montana

Donald M. Jones / Great Horned Owl (Bubo virginianus) female and owlets in nest, central Montana

Donald M. Jones / Great Horned Owl (Bubo virginianus) female and owlets in nest, central Montana

Donald M. Jones / Great Horned Owl (Bubo virginianus) owlets in nest nest, central Montana

Donald M. Jones / Great Horned Owl (Bubo virginianus) owlet portrait, western Montana

Donald M. Jones / Great Horned Owl (Bubo virginianus) owlet, western Montana

Donald M. Jones / Great Horned Owl (Bubo virginianus) owlet pair, western Montana

Kevin Schafer / Great Horned Owl (Bubo virginianus) portrait, Washington

Michael Quinton / Great Horned Owl (Bubo virginianus), Alaska

Shattil & Rozinski / Great horned owl {Bubo virginianus} researcher attaching band to leg, Colorado, USA

Shattil & Rozinski / Three young Great horned owls {Bubo virginianus} in nest, Denver, Colorado, USA

Rolf Nussbaumer / Great horned owl {Bubo virginianus} in Mesquite tree, Texas, US

Tom Vezo / Great Horned Owl (Bubo virginianus) on nest, Florida

Rolf Nussbaumer / Great Horned Owl (Bubo virginianus) on telegraph pole at sunset, Lake Corpus Christi, Texas, USA. March 2003

Rolf Nussbaumer / Adult Great Horned Owl (Bubo virginianus) with fledgling in mesquite tree, Willacy County, Rio Grande Valley, Texas, USA. May 2004

Michael Durham / Great Horned Owl (Bubo virginianus) detail of eye, North America

Hermann Brehm / Great horned owl {Bubo virginianus} Torres del Paine NP, Chile

Hermann Brehm / Great horned owl {Bubo virginianus} Torres del Paine NP, Chile

Tom Vezo / Portrait of a Great horned owl chick {Bubo virginianus} perching on log, Long Island, NY, USA.

Patricio Robles Gil / Great horned owl {Bubo virginianus} Chihuahua desert, Mexico

Larry Michael / Great horned owl {Bubo virginianus} captive, Wisconsin, USA

Larry Michael / Great horned owl {Bubo virginianus} portrait, captive, Wisconsin, USA

Colin Seddon / Portrait of Great horned owl {Bubo virginianus} Captive, Somerset, UK.

LYNN M. STONE / Great horned owl {Bubo virginianus} on grass, Captive.

Philippe Clement / Regurgitated Great horned owl pellets on taiga forest floor {Bubo virginianus} Denali NP, Alaska, USA.

Tom Vezo / Great horned owl {Bubo virginianus} captive, on nest in saguaro cactus, Arizona, USA.

TOM MANGELSEN / Great horned owl in flight (Bubo virginianus) Northwest territories, Canada.

Tom Vezo / Great horned owl at nest hole {Bubo virginianus} captive, Arizona, USA.

Mark Taylor / Great Horned Owl (Bubo virginianus), captive, Scotland. Composite image.

TOM MANGELSEN / Great horned owl with chicks in nest (Bubo virginianus) Oregon

TOM MANGELSEN / Great horned owl in tree (Bubo virginianus) Canada, Saskatchewa

Michael Durham / Great Horned Owl (Bubo virginianus) with House Mouse (Mus musculus) prey, North America

Tom Vezo / Great Horned Owl (Bubo virginianus) perching in tree, North America

Tom Vezo / Great Horned Owl (Bubo virginianus) chick, North America

Tom Vezo / Great Horned Owl (Bubo virginianus) nesting in Saguaro (Carnegiea gigantea) cactus, Tucson, Arizona

Gerry Ellis / Great Horned Owl (Bubo virginianus) portrait, front view, North America

Pete Oxford / Great Horned Owl (Bubo virginianus) perched in a Pine tree, Cotopaxi National Park, Ecuador

Gerry Ellis / Great Horned Owl (Bubo virginianus) in cove of rocks, North America

Konrad Wothe / Great Horned Owl (Bubo virginianus) perching on rock in afternoon light, Colorado

Konrad Wothe / Great Horned Owl (Bubo virginianus), North America

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

Tim Fitzharris / Great Horned Owl (Bubo virginianus) adult perching in a snow-covered tree, British Columbia, Canada

Tim Fitzharris / Great Horned Owl (Bubo virginianus) adult perching in tree, North America

Michael Quinton / Great Horned Owl (Bubo virginianus) chick in defensive posture, spring, Idaho