Their cryptic colouring is so effective that if you blink, you lose them, so I consider myself very fortunate to have found at least a dozen Grayling on top of the Aberbargoed spoil tip during my annual visit last Thursday.

It’s only when these butterflies display their upper wing, with the Meadow-brown-like dot and orange colouring, or perch in an uncluttered spot, like this rock, that they can be seen more clearly.

And, even then, if you’re standing more than a few feet away on a slope covered in dry vegetation and coal-mining spoil, unless you see where they land they can be extremely tricky to locate. The word cryptic was invented for these beauties.