All naturalists have personal obsessions with particular species or activities which may, to non-naturalists, seem ridiculous . In this five-part series Matthew Oates, naturalist and ecologist with the National Trust, meets the people for whom nothing in the natural world is out of bounds. His colleague Andy Foster, known in entomological circles as "Foz " has spent thirty years in search of a rare water-beetle called Agabus brunneus. It lives in fast-flowing gravelly streams in just a handful of places in Southern England and Foz has only found it twice in three decades.

Will it appear on their joint trip to the New Forest and is it all worth it anyway?

Presenter: Matthew Oates
Producer: Brett Westwood
Editor: Julian Hector. Show less