A large, strong-flying butterfly restricted to the Norfolk Broads, although migrants are occasionally seen elsewhere. Pale yellow wings with black veins and blue margins.
This is one of our rarest and most spectacular butterflies. The British race britannicus is a specialist of wet fenland and is currently restricted to the Norfolk Broads. Here the adults can be seen flying powerfully over open fen vegetation, stopping to feed on flowers such as thistles and Ragged-Robin.