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

Markus Varesvuo / Swallow (Hirundo rustica) flying low over water, Israel, March

Angelo Gandolfi / Birdwatchers observing White Storks (Ciconia ciconia) in flight over the Strait of Gibraltar. Mirador El Estrecho, Andalusia, Spain, 2007.

Frederique Olivier / Emperor penguin (Aptenodytes forsteri) procession crossing newly formed sea ice on the way to their breeding grounds, Emperor penguin Antarctica, March.

Philippe Clement / Sandhill cranes {Grus canadensis} flying in formation during migration over Denali NP, Alaska, USA.

Stephen Dalton / Monarch butterfly (Danaus plexippus) female in flight. Did you know? Monarch buttterflies migrate up to 2500 miles from Mexico to Canada.

Hanne & Jens Eriksen / Eurasian wryneck (Jynx torquilla) feeding on ground, during spring migration, Oman, April.

Inaki Relanzon / Migrating wildebeest (Connochaetes taurinus) observed from a hot-air balloon, Masai Mara National Reserve, Kenya, Africa. August 2009

David Tipling / Migrant Reed warbler on passenger on boat {Acrocephalus scirpaceus} Bay of Biscay

Solvin Zankl / Norway lemmings roadkill {Lemmus lemmus} Norway

George Chan / A Kazakh family following ancient migration routes, bringing their possessions and livestock down from the Altai mountains of Xinjiang Province, north-west China. February 2007

Markus Varesvuo / Flock of Eurasian Jackdaw (Corvus monedula) in flight, migration, Hanko, Finland, October