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White-letter hairstreak butterfly

White-letter hairstreak ©John Bridges

White-letter hairstreak butterfly

White-letter hairstreak ©John Bridges

White-letter hairstreak

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The white-letter hairstreak gets its name from the white lines that form a 'W' shape on its underside. It is an elusive butterfly, spending much of its time in the treetops.

Enw gwyddonol

Satyrium w-album

Pryd i'w gweld

June to August

Top facts

Stats

Wingspan: 2.5-3.5cm
Protected in the UK under the Wildlife and Countryside Act, 1981. Priority Species under the UK Post-2010 Biodiversity Framework.

Ynghylch

The white-letter hairstreak is a small butterfly that breeds in elm trees in hedgerows, woodland rides and scrub. It can be hard to spot as it flutters around the treetops, but does come down to lower levels to nectar on flowers like bramble. Adults are on the wing from June to August, and there is only one brood per year. Caterpillars are well camouflaged, looking like young buds and leaves.

What to look for

The white-letter hairstreak is a small, brown butterfly that has white, W-shaped lines on the underside of the wings. The black hairstreak is similar, but sports a row of black spots on the hindwings.

Where to find

Found across England and Wales.

Roeddech chi yn gwybod?

There are five species of hairstreak butterfly in the UK. The name comes from the thin streak of white dashed across the underside of their hindwings, which forms the 'W' shape in the white-letter hairstreak.