Country diary: spellbound in the forest, I see Herne's horned head

Castle Howard, North Yorkshire: A trick of the light evokes the prehistoric shaman's power

When the Wild Hunt erupts from the pages of Susan Cooper's magnificent novel The Dark Is Rising, the throng is led by the towering, antlered figurehead of Herne the Hunter. It's cacophonous, end-of-days stuff - enough to leave any 10-year-old wild-eyed. I next encountered Herne in shamanic guise, swathed in dry ice mist and spookily backlit in the 1984 TV series Robin of Sherwood. With the words, "Nothing's forgotten, nothing is ever forgotten," he took firm root in my teenage psyche.

There's not a whiff of dry ice today. The woods are warm and flickering with butterflies. And yet before my very eyes, an antlered form is emerging, larger than life, from the forest floor, with a metre-long head and a spark of life dancing in the huge dark eye.