Green Hairstreak
Callophrys rubi

Wingspan 27-34mm

Description
This small butterfly always rests with its wings closed and as a result you never see the brown upperwings. The underwings are an iridescent green with a trail of small white marks. The flight is fast and the butterfly is easily lost to view when flying over green vegetation.

Flight Period
Late April to early July

Larval Food plants
Rockrose (Helianthemum nummularium)
Bird's-foot Trefoil (Lotus corniculatis)
Gorse (Ulex europeaus)
Broom (Cytisus scoparius)
Dyer's Greenweed (Genista tinctoria).
Cowberry (Vaccinium vitis-idaea)
Bilberry (Vaccinium myrtillus)
Cranberry (Vaccinium oxycoccus)

Habitat
Calcareous Grassland
Heathland
Moorland (Scotland)

Status
Resident

Earliest Sightings
2011:   8th April      West Yatton Down
2010:   17 April       Pewsey Down
2009:   16 April       Cotley Hill, Heytesbury
2008:   27 April       West Yatton Down 

Brown Hairstreak

(Thecla betulae)

Wingspan  Female 39 - 45mm   Male 37 - 41mm

Description
This elusive small butterfly is the largest of the british hairstreaks. The female upperwings are a deep warm brown and her upper forewings sport large orange flashes, these flashes are absent in the male.The undeside of both sexes is orange with white streaks.

Flight Period
Late July - Late September

Larval food plant
Blackthorn (Prunus spinosa)

Habitat
Woodland edge,  Blackthorn hedgerows

Status
Resident, mainly North Wiltshire

Earliest Wiltshire Sightings
2011:   19th July          Near Minety
2010:   23th July          North Wilts WWT Reserve
2009:   2nd  August    North Wilts
2008:   27th July          North Wilts Wood

Purple Hairstreak

(Neozephrus quercus)

Wingspan
Male 33 -40mm
Female 31 - 38mm

Description
Our largest hairstreak and one of the most abundant, however can be elusive as it spends most of its time in the canopy of oaks. At a distance the butterfly looks either grey if the butterfly is resting with wings closed (underwings) or dark if basking and you see the upperwings. these fast flying butterflies look silvery against the canopy.

Flight Period
Late June to mid September

Larval Food plants
Pedunculate Oak (Quercus robur)
Sessile Oak (Quercus petrae)
Turkey Oak (Quercus cerris)
Evergreen Oak (Quercus ilex)

Habitat
Oak Woodland, Parks and hedgerows with Oak

Status
Resident , widespread and common

Earliest Wiltshire Sightings
2011:    13th June       Bentley Wood
2010:    22nd June      Grovely Wood
2009:    23rd June       Picket Wood
2008:    21st June       Red Lodge Wood
 

White-letter Hairstreak

Satyrium w-album

Wingspan
25 - 35mm

Description
Named after the thin white line resembling a "w" which is visible on the underside of the hindwing. This is the smallest hairstreak and can be the most elusive. The butterfly always feeds and rests with its wings closed. The bottom edge of the hindwings are orange, lined with black that extends to the tail.

Flight PeriodLate June - mid August

Larval food plants
English Elm (Ulmus procera)
Small-leaved Elm (Ulmus minor)
Wych Elm (Ulmus glabra)
Habitat
Woodland edges, rides and roadside verges where the foodplant is present.

Status
Resident

Earliest Wiltshire Sightings
2011:   14th June        Bentley Wood
2010:   22nd June       Grovely Wood
2009:   26th June        Bentley Wood
2008:   5th July            Prickmoor Wood, Chittoe