Introduction

The Green Hairstreak is a widespread but local species in the UK, which has been lost from many sites in the Durham BAP area in recent years.

The butterfly utilises a wide range of habitats and foodplants but is strongly associated with scrub and shrubs. In Durham most colonies are found on heathland where bilberry (Vaccinium myrtillus) is the main foodplant.

Green Hairstreak adults from a single brood are on the wing from mid-May to the end of June. Overwintering as larvae leads to this early emergence.

There is thought to be an association with ants, who bury the pupae, although the range of species is unknown.

Local status

This is an inconspicuous species which may be overlooked, however large colonies are known from a number of sites including Waldridge Fell, Hedleyhope Fell and Hamsterley Forest . Other colonies are known to have been lost through agricultural land-use changes, but recently several new ones have been discovered on brownfield sites, where gorse (Ulex europaeus) or Broom (Cytisus scoparius) are probable foodplants.

Current or recent activity

Butterfly Conservation has undertaken survey work and volunteer training days in recent years, particularly around Hamsterley Forest and Hedleyhope Fell, and has provided management advice to the Forestry Commission and Durham Wildlife Trust.

Threats

•  Destruction of habitat through agricultural and forestry land-use changes.

•  Shading out of larval foodplant (bilberry) through large scale scrub encroachment.

•  Overgrazing of larval foodplant (bilberry).

•  Isolation of remaining colonies from a combination of the above.