The Red Admiral is one of Britain's largest and most vividly marked butterflies, and is unmistakable whether settled or in flight. The males are slightly smaller but otherwise the sexes look similar. When not flying, it usually basks with its wings wide open, exposing soft velvet black upperwings with a brilliant band of scarlet diagonally across each forewing and round the bottom edge of each hindwing. The top corner of the forewing contains striking white patches, and there is a series of black spots in the lower band of scarlet, with a blue patch at the bottom.

The underside of the forewing is a duller version of the uppersides, and is generally less conspicuous. However, when roosting, it is pulled down between the underwings so that only its dark tip is visible. The underwings are then camouflaged to resemble dark bark in shades of mottled brown, grey and black.

Dimensions:
Adult wingspan: 64-78mm.

National:
This is a widespread butterfly throughout much of the British Isles and can be found in a wide range of habitats such as downland, scrub, woodland glades, and gardens. The native population is continually boosted throughout the long season by immigrants from the Continent.

At Durlston:
It is relatively common within the Country Park. Their foodplant is reasonably common throughout much of the Park. Large influxes occasionally occur, the largest in 1996 which occurred over a period of four to five weeks.

The flight period ranges from March to November. The eggs are laid on its favoured foodplant the Common Nettle but may also lay on other plants such as Small Nettle Urtica urens and related species. The larvae form distinctive shaped webs with the leaves. They often pupate within these shelters. All four stages, egg, larva, chrysalis, and adult overwinter.