Alan Murphy / Northern Harrier (Circus cyaneus) female flying, Texas

Anup Shah / African Harrier-Hawk (Polyboroides typus) adult using its legs to probe into cavity nests for young of birds such as swifts and weavers. Masai Mara National Reserve, Kenya. February.

Hanne & Jens Eriksen / Northern harrier (Circus hudsonius) juvenile in flight. Saskatchewan, Canada, August.

Alan Murphy/ BIA / Northern Harrier (Circus cyaneus) flying, Texas

SCOTLAND: The Big Picture / Group of people protesting to raise awareness of Hen harrier (Circus cyaneus) persecution on Grouse moors. Boat of Garten, Cairngorms National Park, Scotland, UK. August 2017.

David Tipling / Hen harrier (Circus cyaneus) female hunting over plain, Hortobagy, Hungary winter

Eric Medard / Hen harrier (Circus cyaneus) male landing next to female, Mayenne, France. May.

Eric Medard / Hen harrier (Circus cyaneus) male passing food to female during courtship. Mayenne, France. (Note poor quality file, small repro only)

Eric Medard / Hen harrier (Circus cyaneus) female in flight, Mayenne, France. March.

Eric Medard / Hen harriers(Circus cyaneus) male in flight with two females, Mayenne, France. March.

Eric Medard / Hen harrier (Circus cyaneus) male in flight, Mayenne, France. May.

Eric Medard / Hen harrier (Circus cyaneus) male in flight, Mayenne, France. May.

Eric Medard / Hen harrier (Circus cyaneus) in flight with prey, Mayenne, France. May.

Eric Medard / Hen harrier (Circus cyaneus) male perched on post, Mayenne, France. May.

Eric Medard / Hen harrier (Circus cyaneus) female in flight, Mayenne, France. May.

Eric Medard / Hen harrier (Circus cyaneus) male in flight, Mayenne, France. May.

Eric Medard / Hen harrier (Circus cyaneus) pair mating, Mayenne, France. May.

Ann & Steve Toon / African harrier-hawk (Polyboroides typus) Kgalagadi Transfrontier Park, South Africa.

Andy Trowbridge / Swamp harrier (Circus approximans) feeding on rabbit prey (Oryctolagus cuniculus). Lake Ellesmere, Canterbury, New Zealand. April.

Andy Trowbridge / Swamp harrier (Circus approximans) perched on rabbit prey (Oryctolagus cuniculus). Lake Ellesmere, Canterbury, New Zealand. April.

Eric Baccega / African harrier hawk (Polyboroides typus) flying. Baringo lake. Kenya.

Eric Baccega / African harrier hawk (Polyboroides typus) taking off, Baringo lake. Kenya.

Andy Trowbridge / Swamp harrier (Circus approximans) perched on prey. Lake Ellesmere, Canterbury, New Zealand. August.

Andy Trowbridge / Swamp harrier (Circus approximans) perched on prey. Lake Ellesmere, Canterbury, New Zealand. August.

Ingo Arndt / Madagascar harrier hawk (Polyboroides radiatus) perced on stump, Masai Mara National Reserve, Keny, Africa

SCOTLAND: The Big Picture / Bird of prey persecution document. Part of Hen Harrier Day 2016, Loch Leven, Kinross, Scotland, UK, August 2016.

SCOTLAND: The Big Picture / People signing a petition calling for a state regulated system of game bird hunting on grouse shooting estates. Hen Harrier Day, Loch Leven, Kinross, Scotland, UK, August 2016.

SCOTLAND: The Big Picture / People signing a petition calling for a state regulated system of game bird hunting on grouse shooting estates. Hen Harrier Day, Loch Leven, Kinross, Scotland, UK, August 2016.

SCOTLAND: The Big Picture / People signing a petition calling for a state regulated system of game bird hunting on grouse shooting estates. Hen Harrier Day, Loch Leven, Kinross, Scotland, UK, August 2016.

SCOTLAND: The Big Picture / People protesting against persecution of birds of prey on grouse shooting estates in Scotland. Hen Harrier Day, Loch Leven, Kinross, Scotland, UK, August 2016.

Gerrit Vyn / Female Northern Harrier (Circus cyaneus) in flight. Sublette County, Wyoming, USA. May.

Gerrit Vyn / Male Northern Harrier (Circus cyaneus) in flight. Sublette County, Wyoming, USA. May.

Gerrit Vyn / Female Northern Harrier (Circus cyaneus) in flight. Sublette County, Wyoming, USA. May.

SCOTLAND: The Big Picture / Hen harrier (Circus cyaneus) adult female silhouetted perched in Scots pine tree, Scotland, UK. July.

SCOTLAND: The Big Picture / Hen harrier (Circus cyaneus) recently fledged chick in flight, Scotland, UK. July.

SCOTLAND: The Big Picture / Hen harrier (Circus cyaneus) adult female in flight over heather moorland, Scotland, UK. July.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) adult female and recently fledged chick in moorland habitat, Scotland, UK. July.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) adult female in flight over heather moorland , Scotland, UK. July.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) adult female and recently fledged chick in moorland habitat , Scotland, UK. July.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) in flight over heather moorland on upland grouse shooting estate, Scotland, UK.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) in flight over heather moorland on upland grouse shooting estate, Scotland, UK.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) in flight over heather moorland on upland grouse shooting estate, Scotland, UK.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) in flight over heather moorland on upland grouse shooting estate, Scotland, UK.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) in flight over heather moorland on upland grouse shooting estate, Scotland, UK.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) in flight over heather moorland on upland grouse shooting estate, Scotland, UK.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) flying close to wind turbine on upland estate, Moray, Scotland, UK.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) flying close to wind turbine on upland estate, Moray, Scotland, UK.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) in flight over heather moorland on upland grouse shooting estate, Scotland, UK.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) in flight over heather moorland on upland grouse shooting estate, Scotland, UK.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) in flight over heather moorland on upland grouse shooting estate, Scotland, UK.

SCOTLAND: The Big Picture / Hen Harrier (Circus cyaneus) in flight over heather moorland on upland grouse shooting estate, Scotland, UK.

Alan Murphy/ BIA / Northern Harrier (Circus cyaneus) flying, Texas

Alan Murphy/ BIA / Northern Harrier (Circus cyaneus) flying, Texas

Bernard Castelein / Madagascar Harrier Hawk (Polyboroides radiatus) female in tree, Reniala Forest, Mangily, Madagascar

Bernard Castelein / Madagascar Harrier Hawk (Polyboroides radiatus) male and female mating in tree, Reniala Forest, Mangily, Madagascar

Bernard Castelein / Madagascar Harrier Hawk (Polyboroides radiatus) male and female mating in tree, Reniala Forest, Mangily, Madagascar

Loic Poidevin / Hen harrier (Circus cyaeneus) in flight, Nome, Alaska, USA, August

Bruno D'Amicis / African harrier-hawk (Polyboroides typus) raiding weaver (Ploceus) nests, Lake Tana Biosphere Reserve. Ethiopia.

Fabrice Cahez / Carrion crow (Corvus corone) mobbing, Hen harrier (Circus cyaneus) female, Vosges, France, May 2015

Bernard Castelein / Hen harrier (Circus cyaneus) in flight, Texel, The Netherlands, May.

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

Alan Murphy / Northern Harrier (Circus cyaneus) male flying, Texas

Charlie Summers / African Harrier-hawk (Polyboroides typus typus) breaking into a Lilac-breasted roller nest. Serengeti, Tanzania.

Anup Shah / African harrier-Hawk (Polyboroides typus) adult using its legs to probe into cavity nests for young of birds such as swifts and weavers. Maasai Mara National Reserve, Kenya.

Charlie Summers / Northern Harrier (Circus cyaneus) hunting over Bosque del Apache reserve, New Mexico, USA. December.

Brent Stephenson / Juvenile Swamp harrier (Circus approximans) flying against a blue sky. Westshore Lagoons, Hawkes Bay, New Zealand, September.

Brent Stephenson / Adult male Swamp harrier (Circus approximans) flying against a blue sky. Waikanae Estuary, Wellington, New Zealand, August.

Lou Coetzer / African harrier hawk (Polyboroides typus) taking off, Chobe River, Botswana, May.

Jussi Murtosaari / Hen Harrier (Circus cyaneus) female on a nest with mosquitos, central Finland, June.

Ralph Martin / Northern Harrier (Circus cyaneus), Schleswig-Holstein, Germany

Alan Murphy / Northern Harrier (Circus cyaneus), Texas

Alan Murphy / Northern Harrier (Circus cyaneus) flying, Texas

Glenn Bartley / Northern Harrier (Circus cyaneus), New Mexico

Rosl Roessner / Northern Harrier (Circus cyaneus)

Mike Wilkes / African harrier hawk (Polyboroides typus) standing on log, Tarangire National Park, Tanzania

David Pattyn / Marsh harrier (Circus aeruginosus) sitting in the reeds. Bulgaria. April

Donald M. Jones / Northern Harrier (Circus cyaneus) female with Eastern Cottontail Rabbit (Sylvilagus floridanus) prey, central Montana

Anup Shah / African harrier hawk (Polyboroides typus) investigating a tree trunk, looking for food, Masai Mara National Reserve, Kenya. March

Anup Shah / African harrier hawk (Polyboroides typus) walking up to a tree, Masai Mara National Reserve, Kenya. March

Anup Shah / African harrier hawk (Polyboroides typus) investigating a cavity to see if there is a nest to steal eggs from, Masai Mara National Reserve, Kenya. March

Scott Leslie / Northern Harrier (Circus cyaneus) female flying, Canada

Andy Trowbridge / Australasian Harrier / Harrier hawk / Swamp Harrier (Circus approximans) portrait. Banks Peninsula, Canterbury, South Island, New Zealand.

Charlie Summers / African harrier hawk (Polyboroides typus), known as the Gymnogene in Southern Africa, immature bird perched on a branch, Lake Manyara National Park, Tanzania

Charlie Summers / African harrier-hawk (Polyboroides typus) perched on a rock. Ngorongoro Crater, Tanzania.

Tony Heald / African harrier hawk / Gymnogene (Polyboroides typus) Etosha National Park, Namibia

Charlie Summers / Northern / Hen harrier / Marsh hawk (Circus cyaneus) at nest with small bird prey for its unseen chicks, Wyoming, USA

Charlie Summers / Northern / Hen Harrier (Circus cyaneus), known locally in North America as the Marsh Hawk, in flight. Bosque del Apache, New Mexico, USA, January.

Charlie Summers / Evidence in the snow of where a Northern Harrier / Marsh Hawk / Hen Harrier (Circus cyaneus) hit its prey, then took off. The long skid marks from the right are the talons dragging, with the wing impr...

Tui De Roy / African Harrier Hawk (Polyboroides typus) landing, Ol Pejeta Conservancy, Kenya

Guy Edwardes / African Harrier-Hawk (Polyboroides typus) in flight Lake Manyara National Park, Tanzania, Africa February

Richard Du Toit / African harrier hawk {Polyboroides typus} juvenile at water, Moremi WR, Botswana

Tony Heald / African harrier hawk (Polyboroides typus) chasing doves from water, Etosha NP, Namibia

Tony Heald / African harrier hawk (Polyboroides typus) juvenile flying down to land or catch prey, Etosha National Park, Namibia, June

Vincent Grafhorst / Madagascar Harrier-Hawk (Polyboroides radiatus) taking off from tree top, Tsiribihina River, Madagascar

Bruno D'Amicis / African harrier hawk / Gymnogene (Polyboroides typus) adult bird showing red facial skin due to excitement, Kaffa, Southern Ethiopia, East Africa December 2008

Scott Leslie / Northern Harrier (Circus cyaneus) female flying, Cape Cod, Massachusetts