Roland Seitre / Pepper Trail, ornithologist, examining dead bird at the National Fish and Wildlife Forensics Laboratory, Ashland, Oregon, USA

Roland Seitre / Richard Stroud carrying out a post mortem on an American bald eagle (Haliaeetus leucocephalus) to discover cause of death at the National Fish and Wildlife Forensics Laboratory, Ashland, Oregon, USA

Roland Seitre / Richard Stroud carrying out a post mortem on an American bald eagle (Haliaeetus leucocephalus) to discover cause of death at the National Fish and Wildlife Forensics Laboratory, Ashland, Oregon, USA

Shattil & Rozinski / Red-tailed Hawk (Buteo jamaicensis) in flight over snowy landscape, Cherry creek state park, Denver, Colorado, USA, October

Tom Vezo / American kestrel {Falco sparverius} juvenile at nest in Saguaro cactus, Arizona, USA

Tom Vezo / American kestrel (Falco sparverius) perched, captive, Raptor Centre, New York, USA

David Tipling / Northern hen harrier {Circus cyaneus} female in flight, looking down, searching for food, Bosque del Apache, New Mexico, USA, January

David Tipling / American Kestrel {Falco sparverius} male perched, Bosque del Apache, New Mexico, USA, January

Mike Read / Aplomado falcon {Falco femoralis} perched, Laguna Atascosa NWR, Texas, USA

Tim Laman / Osprey (Pandion haliaetus) flying from bush in mangroves, Florida Bay, Everglades National Park, Florida, USA.

Tim Laman / Osprey (Pandion haliaetus) perched in bush, Florida Bay, Everglades National Park, Florida, USA.

John Cancalosi / Mexican Spotted Owl (Strix occidentalis lucida) two fledglings perched, USA