New technology gives fresh insights into the great animal migrations. Tom Heap and Helen Czerski discuss the great spectacles of the bird, mammal and insect worlds and consider how they're changing in an era of climate change and habitat destruction.

They're joined by insect migration expert, Will Hawkes, David Barrie, author of Incredible Journeys and the leader of the ICARUS satellite monitoring project, Martin Wikelski from the University of Konstanz. Antonia Bolingbroke-Kent reports from the dangerous songbird migration route over Cyprus while ecologist and concept developer Mark van Heukelm reveals the secrets of the extraordinary fish doorbell and Martha Kearney visits Britain's migration hotspot, Fair Isle.

Producer: Alasdair Cross

Assistant Producers: Toby Field and Georgia Christie

Rare Earth is produced in association with the Open University