Angelo Gandolfi / Four Griffon vultures (Gyps fulvus) flying over Mallos de Aguero cliffs and village of Aguero, Aragon, Spain.

Angelo Gandolfi / Griffon Vultures (Gyps fulvus) flying above the Penafalcon cliffs, Monfrague National Park, Spain.

Angelo Gandolfi / Griffon vulture (Gyps fulvus) flying at sunset, Spain.

Ingo Arndt / Common Starling (Sturnus vulgaris) flock flying in formation to confuse hunting Peregrine Falcon (Falco peregrinus), Europe

Ingo Arndt / Common Starling (Sturnus vulgaris) flock flying in formation to confuse hunting Peregrine Falcon (Falco peregrinus), Europe

Ingo Arndt / Common Starling (Sturnus vulgaris) flock flying in formation to confuse hunting Peregrine Falcon (Falco peregrinus), Europe

Wild Wonders of Europe / Muñoz / Northern gannet (Morus bassanus) colony on Stac Lee, St. Kilda Archipielago, Outer Hebrides, Scotland, UK, June 2009

Wild Wonders of Europe / Green / Northern gannets (Morus bassanus) in flight over cliffs, St Kilda, Scotland, May 2009

Wild Wonders of Europe / Green / Northern gannet (Morus bassanus) colony on cliffs in mist, Hermaness, Shetland Isles, Scotland, July 2009

Wild Wonders of Europe / Green / Northern gannet (Morus bassanus) colony, St Kilda, Scotland, May 2009

Wild Wonders of Europe / Green / Northern gannet (Morus bassanus) in flight over cliffs, St Kilda, Scotland, May 2009

Andy Rouse / Barnacle goose (Branta leucopsis) flock flying in formation, Islay, Scotland

David Tipling / Common guillemots {Uria aalge} returning to their nest ledges, Hornoya Island, Varanger, Norway, March

David Tipling / Common guillemots {Uria aalge} returning to their nest ledges, Hornoya Island, Varanger, Norway, March

Mark Bowler / Grey gulls (Leucophaeus modestus) on beach, Paracas National Park, near Pisco, Ica, Peru, June 2007

Oriol Alamany / Least auklet (Aethia pusilla) flock in flight, Zapadni Bay with Rush Point in the background, Saint George Island, Pribilof Islands, Alaska, USA

Jose B. Ruiz / Bonelli's eagle {Hieraaetus fasciatus} female at nest with chick, male returning to nest, Spain

Alan Williams / Common raven (Corvus corax) pair flying in formation, South Stack, Anglesey, Wales, UK, September

Mike Potts / Cormorant (Phalacrocorax carbo) nesting colony, one bird landing, Little Orme, Llandudno, North Wales, UK

Mike Potts / Common guillemots (Uria aalge) gatherings on breeding ledges, Puffin Island, Anglesey, North Wales, UK

Mike Potts / Chough (Pyrrhocorax pyrrhocorax) in flight over clliffs, South Stack, Anglesey, North Wales, UK

Mike Potts / Chough (Pyrrhocorax pyrrhocorax) in flight over cliffs, South stack, Anglesey, North Wales, UK

Mike Potts / Herring gull (Larus argentatus) colony on cliffs, Puffin Island, Anglesey, North Wales, UK

Mike Potts / Herring gull (Larus argentatus) colony on cliffs, Puffin Island, Anglesey, North Wales, UK

Tim Laman / Scarlet Ibis {Eudocimus ruber} in flight to their roosting sites on small mangrove islands in the Caroni Swamp mangrove forest, passing the moon. Caroni Bird Sanctuary, Trinidad, Trinidad and Tobago....

Wild Wonders of Europe / Unterthiner / Eleonora's falcon (Falco eleonorae) flying over rocks, Andros, Greece, September 2008

Wild Wonders of Europe / Unterthiner / Eleonora's falcon (Falco eleonorae) landing on rock ledge, Andros, Greece, September 2008

Wild Wonders of Europe / O Haarberg / Black-legged kittiwake (Rissa tridactyla) colony on cliff, Langanes peninsula, Iceland, May 2008

Wild Wonders of Europe / O Haarberg / Common guillemot (Uria aalge) and Black-legged kittiwake (Rissa tridactyla) colonies on a cliff, Langanes peninsula, Iceland, May 2008

Nick Upton / Common eurasian cranes (Grus grus) returning to roost at Lac du Der-Chantecoq, Champagne, France at dusk. 2008

Nick Upton / Migrating Common eurasian cranes (Grus grus) flying in "V" formation over Pyrenees mountains on France / Spain border, November 2008.

Nick Upton / Flock of migrating Common Eurasian cranes (Grus grus) in flight, Lac du Der-Chantecoq, Champagne, France.

Nick Upton / Migrating Common eurasian cranes (Grus grus) flying in "V" formation over Pyrenees mountains on France / Spain border, November 2008.

Sebastian Kennerknecht / Tundra Swan (Cygnus columbianus) pair landing, Tule Lake National Wildlife Refuge, California

Sebastian Kennerknecht / Brown Pelican (Pelecanus occidentalis) juveniles flying, Santa Cruz, Monterey Bay, California

Sebastian Kennerknecht / Brown Pelican (Pelecanus occidentalis) adult and juvenile flying, Santa Cruz, Monterey Bay, California

Sebastian Kennerknecht / Brown Pelican (Pelecanus occidentalis) group flying, Santa Cruz, Monterey Bay, California

Donald M. Jones / Snow Goose (Chen caerulescens) migrating in spring, central Montana

Donald M. Jones / Snow Goose (Chen caerulescens) migrating in spring, central Montana

Donald M. Jones / Snow Goose (Chen caerulescens) flock flying, central Montana

Donald M. Jones / Northern Pintail (Anas acuta) group flying, central Montana

Donald M. Jones / Mallard (Anas platyrhynchos) flock flying, central Montana

Donald M. Jones / Canada Goose (Branta canadensis) flock flying, central Montana

Donald M. Jones / Canada Goose (Branta canadensis) flock flying, central Montana

Donald M. Jones / Canada Goose (Branta canadensis) flock flying, central Montana

Juan Carlos Munoz / Northern gannets {Morus bassanus} on cliffs, Noss Island, Bressay, Shetland Islands, Scotland, UK

Juan Carlos Munoz / Green winged macaw (Ara chloroptera) flying, Chapada dos Guimaraes, Mato Grosso, Brazil

Juan Carlos Munoz / Green winged macaw (Ara chloroptera) pair flying, Chapada dos Guimaraes, Mato Grosso, Brazil

Juan Carlos Munoz / Green winged macaw (Ara chloroptera) flying, Chapada dos Guimaraes, Mato Grosso, Brazil

Mike Potts / Oystercatcher (Haematopus ostralegus) flock flying over water to high tide roost, Lavan Sands, Conway Bay, Wales, UK

Juan Carlos Munoz / Green winged macaw (Ara chloroptera) pair flying, Chapada dos Guimaraes, Mato Grosso, Brazil

Eric Baccega / Seabird colony, Isla Ballestas, Ballestas Islands, Peru

Yva Momatiuk & John Eastcott / Sandhill Crane (Grus canadensis) flock flying during migration, Alaska

Yva Momatiuk & John Eastcott / Sandhill Crane (Grus canadensis) flock flying during migration, Alaska

John Cancalosi / California condor (Gymnogyps californianus) flying, Grand Canyon - Vermillion cliffs area, Arizona, USA, Endangered

Jouan & Rius / Young Gannet (Morus bassanus) being encouraged by adult to take off from cliff edge, Shetland Islands, Scotland, UK

Jouan & Rius / Common guillemot (Uria aalge) colony on cliff, Isle of Westray, The Orkney Isles, Scotland, UK

Jouan & Rius / Common guillemot (Uria aalge) colony on cliff, Isle of Westray, The Orkney Isles, Scotland, UK

Bruno D'Amicis / Flock of Common crane (Grus grus) flying in formation at sunrise, NE Germany

Kerstin Hinze / Common Crane (Grus grus) flock flying together in v-formation in the Rügen-Bock-Region in autumn before they continue their annual journey to the south, Western Pomerania, Germany

Kerstin Hinze / Common Crane (Grus grus) flock flying together in the V-formation in the evening from their feeding grounds to their sleeping places in the Rügen-Bock-Region in autumn before they continue their annu...

Patricio Robles Gil / Snow Goose (Chen caerulescens) trio flying in formation, North America

Michio Hoshino / Tundra Swan (Cygnus columbianus) flock flying, Alaska

Luis Quinta / White stork {Ciconia ciconia} in flight over cliffs, Costa Vicentina, Alentejo, Portugal

Ian McCarthy / Gyrfalcon {Falco rusticolus} taking off from rock, Ellesmere Island, Arctic, Canada

Ian McCarthy / Gyrfalcon {Falco rusticolus} taking off from rock, Ellesmere Island, Arctic, Canada

Ian McCarthy / Cranes flying at dawn, Bosque del Apache NWR, New Mexico, USA

Ian McCarthy / Gyrfalcon {Falco rusticolus} taking off from nest on cliffs, Ellesmere Island, Arctic, Canada

Roger Powell / Griffon Vulture {Gyps fulvus} pair flying in parellel courtship flight in front of breeding cliff, Garganta Verde, Sierra de Grazalema, Andalusia, Spain

Roger Powell / Griffon Vulture {Gyps fulvus} pair flying in parellel courtship flight in front of breeding cliff, Garganta Verde, Sierra de Grazalema, Andalusia, Spain

Inaki Relanzon / Fulmar (Fulmarus glacialis) in flight, south coast of Iceland

Inaki Relanzon / Fulmar (Fulmarus glacialis) in flight, south coast of Iceland

Inaki Relanzon / Common cranes (Grus grus) flying in formation at sunrise, Hornborgasjön Lake, Sweden

Steven Kazlowski / Sea birds flying around Cape Thompson in the morning, 26 miles south of Point Hope, Chukchi Sea. Arctic Ocena, Alaska

Steven Kazlowski / Black-browed albatross (Thalassarche melanophrys) in flight off New Island, Falkland Islands

Steve Knell / Kittiwake (Rissa tridactyla) colony on cliffs in Northumerland, one in flight carrying nesting material. Northumberland, July

Gerry Ellis / Sandhill Crane (Grus canadensis) flock flying along the central flyway silhouetted at sunset, North America

Konrad Wothe / Snow Goose (Chen caerulescens) flock flying during migration, Bosque del Apache National Wildlife Refuge, New Mexico

Konrad Wothe / Snow Goose (Chen caerulescens) flock flying during migration, Bosque del Apache National Wildlife Refuge, New Mexico

Jose B. Ruiz / European bee eater {Merops apiaster} flying to nest with prey. Alicante, Spain

Yva Momatiuk & John Eastcott / Sandhill Crane (Grus canadensis) flock flying past snow and ice covered face of Mt McKinley at sunrise, during the birds' fall migration south, Denali National Park, Alaska

Tom Vezo / Mew Gull (Larus canus) group silhouetted at sunset in La Jolla, California

Tom Vezo / Mallard (Anas platyrhynchos) male and two females flying, Arizona

Barrie Britton / Demoiselle cranes {Anthropoides virgo} on migration flying over the Himalayas, Nepal, c 2004

Solvin Zankl / Flock of wildfowl flying in formation at sunset, Bass Rock, Scotland UK

Chris Gomersall / Group of Atlantic puffin (Fratercula arctica) in flight at breeding colony. Island of Flatey, northern Iceland. July 2006

Patricio Robles Gil / Greater Flamingo (Phoenicopterus ruber) flock flying, Ria Celestun Biosphere Reserve, Yucatan-Campeche, Mexico

Tom Vezo / American White Pelican (Pelecanus erythrorhynchos) flock flying, Saskatchewan, Canada

Konrad Wothe / Sandhill Crane (Grus canadensis) flock flying during migration, Bosque del Apache National Wildlife Refuge, New Mexico

Konrad Wothe / Snow Goose (Chen caerulescens) flock flying during migration, Bosque del Apache National Wildlife Refuge, New Mexico

Konrad Wothe / Snow Goose (Chen caerulescens) flock flying during migration, Bosque del Apache National Wildlife Refuge, New Mexico

Konrad Wothe / Snow Goose (Chen caerulescens) trio flying, Bosque del Apache National Wildlife Refuge, New Mexico

Konrad Wothe / Sandhill Crane (Grus canadensis) flock flying in formation during migration, Bosque del Apache National Wildlife Refuge, New Mexico

Konrad Wothe / Sandhill Crane (Grus canadensis) flock flying in formation during migration, Bosque del Apache National Wildlife Refuge, New Mexico

Konrad Wothe / Snow Goose (Chen caerulescens) flock flying overhead, Bosque del Apache National Wildlife Refuge, New Mexico

Martin H Smith / Sand martins flying above cliffs with nest holes {Riparia riparia} Norfolk, UK