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White-letter Hairstreak

(Satyrium w-album)

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.

White-letter Hairstreak butterfly on white flower White-letter Hairstreak ©John Bridges
White-letter Hairstreak butterfly
White-letter Hairstreak ©John Bridges
White-letter Hairstreak butterfly

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Overview

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. Caterpillars are well camouflaged, looking like young buds and leaves.

Key Facts

  • 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.
  • 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.
  • Wingspan: 2.5-3.5cm

Status

Protected in the UK under the Wildlife and Countryside Act, 1981. Priority Species under the UK Post-2010 Biodiversity Framework.

Seasonality

Adults are on the wing from June to August, and there is only one brood per year

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