White Letter Hairstreak

WHITE-LETTER HAIRSTREAK (SATYRIUM W-ALBUM)

LOCAL BIODIVERSITY ACTION PLAN

Links to associated HAPs

Ancient Semi-natural Broadleaved Woodland, Ancient Hedgerows

Ecology

Appearance
The English name refers to the white scales at the base of the hind wings that form a distinct 'W'. It is reliant on the elm as its foodplant, in particular the Wych Elm (Ulmus Glabra) and will often breed on the same Wych Elm year after year. They do not stray far from the birth tree although will go to bramble and flowering privet on the edge of woods. They only have one brood per year and lay eggs in August that do not hatch till the following spring when the caterpillars hatch out and feed on Elm. The larva are densely covered in short white hairs, the back is prominently ridged and when fully grown reach 15mm

Habitat
White-letter hairstreak butterflies prefer areas with elm trees and plants providing nectar present and can be found in many habitats including, meadows, hedgerows and woodlands.

Food
They feed on honeydew left by aphids on leaves of trees, especially English elm, small-leaved elm and wych elm. They will also feed on the nectar from other plants nearby such as, creeping thistle, bramble and marjoram.

Life Style
White-Letter Hairstreak can be seem on the wing from early July through to early August although spend the majority of their time basking in the high leaves and branches of the Elm.

Current Status

The white-letter hairstreak has declined in the United Kingdom as a result of Dutch Elm Disease destroying its larval foodplant. In Cheshire it has a limited distribution.

The white-letter hairstreak depends upon elm as the larval foodplant - it is easier to locate the larvae than the adults flying around the tops of trees later in the season and as a consequence may be under-recorded.

The White-letter hairstreak was added to the UKBAP priority list in 2007.

Threats

* Loss of elm trees through Dutch elm disease and felling operations.
* Loss of suckers through cutting of hedgerows.

How are we helping to conserve the White-letter Hairstreak in the Cheshire region?

* Training days on identification and monitoring / recording techniques are to be held.
* Cheshire and Peak District Branch of Butterfly Conservation are monitoring white-letter hairstreak at known sites and searching for new colonies.
* Records are collated by the Cheshire and Peak District Branch of Butterfly Conservation. Records will also be held at rECOrd.
* Ongoing monitoring at key sites.

Objectives, Targets and Actions

Objectives, targets and actions to help conserve the white-letter hairstreak in the Cheshire region can be found on the Biodiversity Action Reporting System (BARS) along with full details of our progress so far.

How to find out more about the White-letter Hairstreak

Vale Royal Borough Council Elm Species Recording card
Butterfly Conservation species data pdf
UK Butterflies - http://www.ukbutterflies.co.uk/species.php?vernacular_name=White-letter%20Hairstreak
Cheshire & Peak District branch of Butterfly Conservation, local information - www.butterfly-conservation.com/species/speciesdetails/ches/whiteletterhairstreak.htm?

How can you get involved?

Joan Fairhurst is collating records on mature elm trees in Cheshire. It is becoming clear that some trees have survived the ravages of Dutch Elm Disease, the Wych Elm in particular. Elm trees are important for the survival of the White Letter Hairstreak.

Contact details

LBAP Chair
Cheshire Wildlife Trust - 01948 820 728

References & Glossary
Bourne, N. Kirkland, P. & Warren, M. (1996) Action for Butterflies - Butterfly Conservation's Guidelines for producing Regional Action Plans. British Butterfly Conservation Society, Wareham
Guest, J. (1997) pers comm.
HMSO (1995): Biodiversity: The UK Steering Group Report, Volume 1: Meeting the Rio Challenge, London.
HMSO (1995): Biodiversity: The UK Steering Group Report, Volume 2:Action Plans, London.
Rutherford, C.I. (1983) Butterflies of Cheshire 1961 - 1982. The Lancashire and Cheshire Entomological Society
Shaw, B. (1995, 1996) Cheshire Butterfly Atlases 1994 & 1995. British Butterfly Conservation Society (Cheshire and Peak District) Cheshire
http://www.ukbutterflies.co.uk/species.php?vernacular_name=White-Letter%20Hairstreak
Davies, M.G. (1992) The White-letter hairstreak butterfly. Butterfly conservation