null: Spring comes to the Dales and North York Moors National Parks, the season when the parks' animals must find food, a mate and raise a family. Adders battle to secure a mate, while grebes prefer a mating dance. On the coast, a quarter of a million sea birds arrive to nest, many returning to exactly the same nest site every year. Up around Malham Tarn, an injured, pregnant roe deer is desperately seeks Spring's green shoots to survive.