Brown hairstreak: the rare butterfly quietly retaking London and beyond

The male brown hairstreak seen from above and underneath (top) and the female (bottom). Photograph: Nature Photographers Ltd/Alamy

One of the most elusive and nationally scarce butterflies is quietly retaking London and the Thames corridor. The brown hairstreak is a beautiful, ginger-streaked insect that usually lurks unseen in the treetops in late summer.

It is easier to find the hairstreak’s minuscule white eggs than to find the butterfly – but only now, in midwinter, when the sea-urchin-like ova can be found on the bare branches of blackthorn, which thrives in hedges and copses on clay soils.