The Butterflies of Gloucestershire

White Letter Hairstreak Satyrium (strymonidia) w-album
	24 July 1993	15 July 1984

Habitat

White Letter Hairstreaks are found on and around elm trees in hedgerows and woods. Both English Elm (Ulmus procera) and Wych Elm (Ulmus glabra) are used as larval foodplants.

The butterflies tend to fly occasionally and briefly around the tops of the elms, so patient observation is often necessary to find them. One of their favourite nectar sources is privet (Ligustrum vulgare), but they also feed on aphid honeydew up in the trees.

The Wych Elm to the left of this track
supports White Letter Hairstreaks

Conservation Issues

Elm disease (a fungal infection spread by a beetle) has had a devastating effect on the habitat for this species, with almost all mature English Elm trees now long gone. The damage is particularly noticeable in hedgerows in the Severn vale.

There is a lot of regrowth which itself gets attacked after a few years, but the succession of elm regrowth has so far maintained sufficient habitat to enable the butterfly to survive.

Flight Period
Late June to mid August. It is easier to find it nectaring on flowers early in this period.

Distribution
The White Letter Hairstreak is very under-recorded because of its habits and its habitat. It occurs throughout the area, and may usually be found if searched for in places where there is plenty of apparently healthy elm regrowth.