Purple Hairstreak

• Latin name: Neozephyrus quercus
• Family group: Hairstreaks
• Countries: England, Scotland, Wales, Ireland
• Size: Small

Resident

Range expanding in Britain.

This handsome butterfly is widely distributed throughout southern areas wherever there are oak trees; even a solitary tree may support a colony. It is frequently overlooked as adults remain largely in the canopy where the main adult food source is honeydew; they fly more commonly in the evening of a warm summer's day. They are only driven down to seek fluid and nectar during prolonged drought, as occurred in 1995-6.

There has been a recent increase in records and an extension of the range of this butterfly especially in the English Midlands and south-west Scotland, even in urban areas (including London) which may be related to improvements in atmospheric quality.

Conservation status

• UK BAP status: not listed
• Butterfly Conservation priority: low
• European threat status: not threatened
• Protected in Northern Ireland

European/world range

The Purple Hairstreak occurs from North Africa to Southern Scandinavia and across central Europe to Asia Minor. It is stable throughout much of Europe but has declined in several countries and is spreading at the northern edge of its range.

Foodplants

The Purple Hairstreak is restricted to oak trees including both the native species, Sessile Oak (Quercus petraea) and Pedunculate Oak (Q. robur), and the introduced Turkey Oak (Q. cerris). Evergreen Oak (Q. ilex) also may be used.

Habitat

Colonies of Purple Hairstreak may be found in woodlands where sufficient oaks remain, in ancient park woodlands, associated with hedgerow and lane-side oaks, on heathland oak scrub, oak screens along the edge of conifer plantations, and even in towns including central London.

In groups of oaks, there is usually a favourite tree and isolated oaks (which may be survivors from when the site was more heavily wooded) may support colonies that have become self-contained on the same tree for many years.

In Ireland, the butterfly tends to prefer small oaks and colonies are often small. Adults will perch and feed on Ash and elms in regenerating woodland because they are fast growing and out-top oak, but oak is needed for breeding.