“Silver-studded,” said the man hunched over his phone, pointing at a patch of red fescue grass. “Clouds of ’em.” Without looking up, he waved his arm over the common of Prees Heath. A stiff breeze ruffled the grass and carried the drone from surrounding trunk roads as sunlight flashed through scudding clouds. The day was as blue and silver-studded as the butterflies. Plebejus argus, the silver-studded blue butterfly, has its last outpost in the English Midlands here.
Plebejus suggests commoner and argus is perhaps keeping watch, but like the dwellers of many heathland commons, life for the butterflies here hung by a thread. Because of callous exploitation by collectors in the past, this location was long kept secret but conservation work to restore the heathland has helped the butterflies, and now there are waymarkers pointing them out.
But first, as if needing to be conjured by the mysterious man with the phone, they had to appear. Suddenly, one – like a scrap of sky, not of blue pigment but a refraction from wing scales, a trick of the light – flew a hand’s width above the grass; then three; then a dozen together, all flying low, as if held by some gravitational pull to a patch only a few metres square. The reason for this turned out to be female; she was dark, hindwings suffused blue, with coppery marks at the edge and perched on a grass stem. The males skittered around briefly, then settled on surrounding stems, heads down, wings open, prepared for take-off. They were brilliantly azure and bordered black and white above, and pale with light and dark spots below. They got their common name from silvery dots on the hindwings.
The markings of these particular butterflies are very similar to those of P argus masseyi, a form of silver-studded blue once also found in parts of northern England but now extinct there, which made the Prees Heath survivors even more extraordinary. Regal commoners of fescue, bird’s-foot trefoil and rosebay willowherb during summer flying time, these butterflies, nurtured by ants and now protected, are dwellers of the heather, heathen souls of the heath; “clouds of ’em”.
