Look for the smallest butterflies with a fast, erratic flight pattern, typically around grasslands and woodland edges. Males display a distinctive bluish shimmer on their dark brown wings when open, whereas females are more uniformly colored. Both sexes have black-spotted, silver ventral sides when their wings are closed.

Both male and female Holly Blues and male Common Blues have blue upperwings and look blue in flight. Female Common Blue butterflies vary from brown to mostly blue, but always have a distinctive series of orange spots towards the edges of their wings, that Holly Blues don’t have. The key distinguishing feature is the undersides of the hindwings.

Living up to its name, this butterfly is the commonest blue found in the British Isles. While the male has bright blue uppersides, the female is primarily brown, with a highly variable amount of blue. This is the most widespread Lycaenid found in the British Isles and can be found almost anywhere, including Orkney.