The grayling is fairly widespread on the New Forest and the Dorset heaths and is also found on the heaths of north Hampshire and southern England. Elsewhere in the UK it is found on the coast. However it is decreasing in many places, especially inland sites, and the New Forest is a particular stronghold for it.
Graylings are quite common on large areas of open heathland in the New Forest. They require dry, barren areas with broken ground of soil, sand or gravel and areas of grasses for the caterpillars. The management of the heaths to keep them open and free from invading trees, scrub, bramble and bracken is particularly important for this species. If an area of open ground becomes slightly shaded with scrub then the grayling disappears.
Old names for this species give a clue to how well camouflaged it is when it rests on the ground, always with its wings closed. Rock-eyed underwing and black-eyed marble are two of them. The underside of the wings is marbled with brown and grey and the upper wing has two black eye-spots. It is remarkable how this fairly large butterfly seems to disappear from view when it lands and closes its wings, even on an open track.
Look for it on any open heathland in July or August. It is best to slowly walk along gravelly tracks through the heather.