Things With Wings

UK wildlife photography community at thingswithwings.uk — loading the latest sightings…

White-letter Hairstreak · Field Guide · Things With Wings

🦋

White-letter Hairstreak

Satyrium w-album

Not yet photographed by the community

White "W" on underside; elm-dependent and scarce.

Species Profile

Nationally Scarce B; populations have declined significantly due to Dutch Elm Disease reducing host plant availability.

Lifespan: Approximately 2 weeks as an adult butterfly in the wild
Size & Weight: Wingspan 27–32 mm
Habitat: Woodland edges, scrub, and hedgerows where elm trees are present, typically in warm, sheltered locations.
UK Distribution: Found in southern England, particularly in the Midlands and south-east, with a northern limit around Yorkshire; resident but with fluctuating populations.
Diet: Adults feed on honeydew secreted by aphids and small amounts of nectar from flowers; caterpillars feed exclusively on elm leaves (mainly Ulmus minor and U. procera).
Predators: Small birds, spiders, and parasitic wasps targeting caterpillars and pupae
Mating Season: July to August
Breeding: Females lay single eggs on elm twigs in late summer; eggs overwinter and hatch in spring; single brood per year; caterpillars feed April to June.
Behaviour: Adults are elusive and spend much time in the canopy feeding on aphid honeydew rather than flowers, making them difficult to observe. Males perch on elm branches and dart out to intercept females. They are most active in warm sunshine.

Sources and editorial status

The short identification summary comes from the Things With Wings species catalogue. The extended species profile is AI-assisted and has not been individually reviewed by a wildlife expert, so verify important identification or conservation details with the specialist sources below.

Profile generated 22 June 2026

Spotted an error? Tell us so it can be corrected.

🦋

No photos yet

Be the first to photograph a White-letter Hairstreak and share it with the community.