In late summer warmth, sheep lie in the shade of stunted hawthorns. Others meander past dried-up hollows, granite moorstone covered in sun-crisped lichens and stonecrop, and coarse grasses and prickly gorse, towards favoured turf around the ancient circle of Nine Stones. Prehistoric remains on this eastern side of the moor hint at the importance of this quiet, airy upland for early farmers, for seasonal grazing and for ceremonial observances. Rectilinear boundaries, remnants of cairns and a tumulus overlook fields and woods across the Lynher Valley, mostly green but with pale stubble after recent harvesting of grain and straw. About 50 wind turbines are scattered across the panorama, and acres of solar panels gleam beyond Bray Shop, closer to Callington and Kit Hill. Water in the stream from Redmoor Marsh is easily crossed, and the massive stone bank separating open land from old enclosures is topped by bright green polypody ferns, pink flowers of ling (out of reach of nibbling sheep) and scarlet rowan berries. Red admirals and tortoiseshells fly almost as high as Fox Tor, where the sound of traffic carries uphill from the A30 – the main route to and from Cornwall’s busy resorts. Satellite dishes of Morwenstow GCHQ station glow white in the far distance and, nearer to the south, Caradon Hill’s mast protrudes above the rocky skyline of King Arthur’s Bed, Kilmar and Trewortha tors. From the nearby summit with a ring cairn, through a gap by Hawk’s Tor, there is even a glimpse of Morwell woods in the Tamar Valley. Westward, beyond partially felled coniferous plantations at Halvana, the undulating summit of Brown Willy is the highest point of the county. No swallows are apparent until the moorland edge, where a suckler herd of cows and their maturing calves congregate close to Tresellern farmstead. Swallows twitter and hunt for insects, swooping across the ford from Watery Marsh, gliding around browned-off beech trees and mildewed oak leaves, and soaring over banks of brambles laden with ripening blackberries to dart among thistledown that floats above fields rowed up with a last cut of grass for silage.