Snakes in the bracken

Big Moor, Derbyshire The glimpse resolved itself into a knot of plump, scaly flesh, two adders wound around each other

"It is the bright day that brings forth the adder," Brutus warned in Julius Caesar, "and that craves wary walking." As I crossed the white dome of Big Moor, snakes were the last creatures on my mind. That morning's blue skies had given way to dark, scudding clouds and a keen wind. Twelve hundred feet up, it felt too cold for snakes. I sank my chin into my jacket and walked less warily and more briskly.

The moor, rich with curlew and lark, is split by Bar Brook, dammed in the past but no longer; it descends to enter a smaller reservoir, sheltered with birch and willow. Here on the ground were sheets, randomly placed, of corrugated iron. This looks like building waste, but the tin was in fact placed deliberately 20 years ago to attract adders for a census. The warm air building up underneath was thought to be irresistible, herpetologically speaking.