John Cancalosi / American toads (Anaxyrus americanus), several males competing to mate with female, Maryland, USA, April.

Hugh Pearson / BBC Producer, Hugh Pearson, recording sound of Cape gannets (Morus capensis) Bird Island, off the coast of the Eastern Cape, South Africa, January

NEIL NIGHTINGALE / Producer Neil Nightingale and film crew filming David Attenborough on Ellesmere Island, Canada, presenter of BBC 'Private Life of Plants', 1994

John Cancalosi / American toads (Anaxyrus americanus), several males trying to mate with female, Maryland, USA, April.

John Cancalosi / American toads (Anaxyrus americanus), two males attempting to mate with female, Maryland, USA, April.

John Cancalosi / American toads (Anaxyrus americanus), males competing to mate with female, Maryland, USA, April.

Konrad Wothe / Male Great spotted woodpecker (Dendrocopos major) drumming and stretching wings, Bavaria, Germany, March.

David Fleetham / Sound recording device from University of Hawaii anchored on reef off Hawaii.

Nick Upton / Two pairs of Avocets (Recurvirostra avosetta) foraging close to one another in a shallow lake, showing some territorial interaction, Gloucestershire, England, UK, March.

Laurent Geslin / Sound recording birdsong, Caprivi strip, Namibia

Laurent Geslin / Sound recording birdsong, Caprivi strip, Namibia

Mark Carwardine / BBC film crew filming and sound recording Grey whale (Eschrichtius robustus) at surface, San Ignacio Lagoon, Baja California, Mexico, February 2009