The Grayling flies from late June to early September; they are especially present in August.
It is a large butterfly that likes to sit on the ground.
The Grayling always has its wings closed.

When they land Graylings snap their wings shut, but raise the forewings so that the eyespot near the apex is visible.
This way, any bird which attacks the butterfly, is likely to aim at the eyespot rather than at the body.
Once the Grayling feels safe, it lowers the forewing to hide the eyespot behind the hindwing.

Brucherbierg-Lallengerbierg Nature Reserve, Luxembourg, 12 August 2024