It's seventy years since Friend Owl (in the film Bambi) identified a phenomenon that has been evident in nature since the earliest times. With the spring thaw, Bambi and Thumper are bewildered by the giddy skittishness of the creatures of the forest. Owl enlightens them...
"They're twitterpated! Nearly everybody gets twitterpated in the springtime... you're walking along, minding your own business. You're looking neither to the left, nor to the right, when all of a sudden you run smack into a pretty face. Woo-woo! You begin to get weak in the knees. Your head's in a whirl... You're knocked for a loop!" "Gosh, that's awful", says Thumper.
Young couples share their stories of falling in love in the springtime - Sandy and Alex are still students, head-over-heels and planning a life together; Jo and Amit were 'knocked for a loop' under a tree surrounded by squirrels and birds.
Biological anthropologist Helen Fisher traces the behaviour described by Friend Owl back to humanity's origins and finds evidence of its effect in our brain chemistry. Woodland ranger Simon Bateman, on a sunny spring morning, finds the promise of new life in the flora and fauna under his protection.