Brown hairstreak

Brown hairstreak butterfly

Brown hairstreak ©Philip Precey

Brown Hairstreak butterfly

©Philip Precey

Brown hairstreak

Scientific name: Thecla betulae
The brown hairstreak is an elusive butterfly that spends much of its time in the treetops feeding on aphid honeydew.

Species information


Wingspan: 3.6-4.5cm

Conservation status

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

When to see

July to September


The largest of the UK's hairstreaks, the brown hairstreak is an elusive butterfly that spends most of its time either high in the tops of large ash trees (called 'master trees'), or among thick hedges. It is found at woodland edges and along hedgerows in southern England from late July until November. Adults feed on honeydew from aphids, while caterpillars feed exclusively on blackthorn.

How to identify

The brown hairstreak is a large hairstreak, with brown upperwings and small 'tails' protruding from the hindwings. Females have a brilliant orange patch in the top corner of each forewing. The underwings are a distinctive bright orange, with two white lines streaked across them.


Found in scattered locations in southern England and Wales.

Did you know?

Female brown hairstreaks lay conspicuous, round, white eggs on young blackthorn shoots. Looking like blackthorn leaves, the older caterpillars are extremely well camouflaged and feed only at night.