It is worth looking up at prominent Ash trees along wood edges to see if small clusters of adults may be flitting around. They congregate to mate and feed on aphid honeydew. Adults also sometimes feed lower down on flowers such as Hemp-agrimony, Common Fleabane and Bramble. The females are most frequently seen as they disperse widely along hedgerows where they lay conspicuous white eggs on young Blackthorn shoots.

The butterfly often rests with its wings closed showing orange-brown underwings with two wavy white streaks and small tails. Uppersides are brown with an orange mark.

It is locally distributed in southern Britain and mid-west Ireland and has undergone a substantial decline due to hedgerow removal and annual flailing, which removes eggs.

Size and Family

  • Family: Hairstreaks
  • Size: Small/Medium
  • Wing Span Range (male to female): 38-40mm

Conservation status

  • Section 41 species of principal importance under the NERC Act in England
  • Section 7 species of principle importance under the Environment (Wales) Act 2016
  • GB Red List (2022): Vulnerable     
  • Butterfly Conservation priority: High                    
  • European Status: Not threatened                           
  • Protected under Schedule 5 of the 1981 Wildlife and Countryside Act (for sale only)

Caterpillar Foodplants

The Butterfly breeds on the young growth of Blackthorn (Prunus spinosa) and occasionally other Prunus species such as Bullace (P. domestica).

Lifecycle

Habitat

Hedges, scrub and woodland edge where Blackthorn is prominent and not flailed every year.

Distribution

  • Countries: England, Wales, and Ireland
  • Restricted in the UK to three main centres: south-west Wales, Devon/Somerset and Surrey/Sussex. Other smaller populations occur around Oxford and on Salisbury Plain.
  • Abundance trend: 0.4% (1983-2019)
  • Distribution trend: -0.3% (1994-2019)
Brown Hairstreak (female/upperwing) - Iain Leach

Brown Hairstreak (female/upperwing)

Brown Hairstreak (female/upperwing) - Iain Leach

Brown Hairstreak (female/upperwing)

Brown Hairstreak (male/upperwing) - Pete Withers

Brown Hairstreak (male/upperwing)

Brown Hairstreak (underwing) - Adam Gor

Brown Hairstreak (underwing)

Brown Hairstreak (female/underwing) - Bob Eade

Brown Hairstreak (female/underwing)

Brown Hairstreak (underwing) - Iain Leach

Brown Hairstreak (underwing)

Brown Hairstreak (female/underwing) - Bob Eade

Brown Hairstreak (female/underwing)

Brown Hairstreak (egg) - Gilles San Martin

Brown Hairstreak (egg)

Brown Hairstreak (egg) - Gillian Thompson

Brown Hairstreak (egg)

Brown Hairstreak (caterpillar) - Ervin Szombathelyi

Brown Hairstreak (caterpillar)

Brown Hairstreak (caterpillar) by Peter Eeles

Brown Hairstreak (caterpillar)

Brown Hairstreak (pupa) by Peter Eeles

Brown Hairstreak (pupa)