Country diary: A simple picnic in a miniature jungle

‘Chimney sweepers – geometrid moths with sooty wings tipped with a dash of white – settle to lay eggs.’ Photograph: Phil Gates

A geometrid moth caterpillar undulates through the grass. Grip with front legs. Cast off astern. Loop the body, drawing in the tail, and grip. Let go for’ard. Stretch to measure its length, with geometric precision, along the leaf. Grip again for’ard. And repeat. I tap the grass and the caterpillar freezes, relying on its resemblance to a dead twig to keep it safe.

Dappled shade cast by a hawthorn makes this a perfect spot to sit and rest on a sultry summer afternoon. Nothing fancy for a picnic, just a cheese and chutney roll, a pear and a carton of orange juice, but the company is endlessly fascinating. The calcareous grassland of this ancient wood pasture, unploughed for centuries, is teeming with invertebrate life.