Our smallest resident butterfly is easily overlooked, partly because of its size and dusky colouring, but partly because it is often confined to small patches of sheltered grassland where its sole foodplant, Kidney Vetch, is found.  Males set up territories in sheltered positions, perching on tall grass or scrub.  Once mated, the females disperse to lay eggs but both sexes may be found from late afternoon onwards in communal roosts, facing head down in long grass. The butterfly tends to live in small colonies and is declining in most areas.