Steven Cheshire's British Butterflies
British Butterflies: Species: Species Account - The Black Hairstreak:
Black Hairstreak
Satyrium pruni (Linnaeus, 1758)

Black Hairstreak egg.
ova
  Black Hairstreak caterpillar.
larva
  Black Hairstreak chrysalis
pupa
Black Hairstreak
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Nomenclature
Insecta: Lepidoptera : Family Lycaenidae: Subfamily Lycaeninae : Genus Satyrium: Species pruni:
Description
The Black Hairstreak is an elusive butterfly flying only in bright sunshine... its short jerky flight flitting between the tops of Blackthorn (Sloe) thickets and hedgerows often being the only sign of its presence. This combined with a short adult flight period of little more than two , at best three weeks from the middle of June to early July makes the sighting of this species highly prized by butterfly enthusiasts. In recent years there has been a trend for a slightly earlier adult flight period possibly as a result of recent warmer spring months.

The Black Hairstreak and 
White-letter Hairstreak are similar in appearance and size and they may be encountered together in some locations as their flight period and habitats do overlap. Both species rarely open their wings so identification is dependant upon the characteristic pattern of the hind underwing.

The main difference between the two species is evident near the distinctive tails on the underside of their hind wings. The Black Hairstreak has a clearly defined row of black spots along the inner edge of the orange band while the White-letter Hairstreak clear has a continuous jagged black line. The 'hairstreak' of the White-letter Hairstreak  is also has a clearly defined sideways W.

The Black Hairstreak can be very difficult to spot because they spend much of their time up in the tree canopy feeding on the honeydew produced by aphids. To see them at eye level, wait until early evening just as the sun begins to set... many individuals will come down from the tree tops to nectar on various flowers such as Wild Privet Dog Rose Bramble and White/Red Bryony. Individuals tend to crawl through the foliage moving from flower to flower as they feed.

Black Hairstreaks will also venture beyond the tops of the Blackthorn thickets, especially in the early evening when individuals may be seen flying low down across small meadows towards Blackthorn hedgerows beyond. Those lucky enough to see this may see individuals stopping to bask in sheltered hollows within the meadow of feeding on low growing Blackberry, Privet, Black / White Bryony and other flowers which provide rich sweet nectar.

Butterflies may be seen quite early in the morning from 7am often sunning themselves in a distinctive fashion closed wings angled towards the sun to get the best possible exposure. The adult butterflies soon become tatty as they age.
Habitat
The Black Hairstreak has specific environmental requirements and colonies tend to breed year after year in the same small area of habitat.

It prefers dense mature stands of Blackthorn growing in sheltered positions alongside rides and clearings in woods and woodland edges. Check the flowers of Bramble and Wild Privet for nectaring individuals.
Distribution
The Black Hairstreak has always had a very small range of distribution in England being found primarily in the former Royal Forests in the East Midlands. Due to changes in woodland management over the last 50 to 100 years the Black Hairstreak is now restricted to a narrow belt of woodlands between Oxford and Peterborough.
Where to see the Black Hairstreak in the British Isles
Northamptonshire: Glapthorn Cow Pasture, Short Wood, Fermyn Woods, Yardley Chase and Salcey Forest
Cambridgeshire: Monk's Wood and Brampton Wood
Oxfordshire: Finemere Wood and Whitecross Green Wood, Bernwood Forest, Bernwood Meadows and Oxford Lane


One of the most reliable sites and probably most visited by butterfly enthusiasts to see Black Hairstreak is Glapthorn Cow Pasture in Northamptonshire.
 
Black Hairstreak numbers at Salcey Forest have dropped dramatically in recent years.
Other notes
A special effort is required to visit the key sites for this species due to its very limited distribution. Good weather is also required as is a lot of patience to see this butterfly at close quarters.
Lifecycle chart
ovaovaovaovalarvaelarvaepupaadultadultovaovaovaovaovaova
 
Flight chart
JanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
The lifecycle and flight charts should be regarded as approximate guides to the Black Hairstreak in Britain. Specific lifecycle states, adult emergence and peak flight times vary from year to year due to variations in weather conditions.
IUCN category status 2010 5   IUCN category status 2007 34
Endangered Endangered

5Fox, R., Warren, M., Brereton, T. M., Roy, D. B. & Robinson, A.
(2010) A new Red List of British Butterflies. Insect Conservation and Diversity.
Endangered Endangered

3Fox, R., Warren, M & Brereton, T.
(2007) New Red List of British Butterflies. Butterfly Conservation, Wareham.

4More information about IUCN categories.
Wingspan
34-40mm
UK status
Resident
Larval foodplants
Eggs are laid singly on the underside of a forked branch of Blackthorn (Prunus spinosa) or Wild Plum (Prunus domestica) bushes in June. They hatch early the following spring and beings to feed on the leaf buds and later the fully developed leaves.

The pupae resembles a bird dropping which makes it difficult to find especially among the vigorous growth of a Blackthorn thicket. Despite this it is this part of its lifecycle which is the easiest to find.

It is thought that as much as 80% of pupae are lost to predation from woodland birds such as warblers and tits.
Butterflies of Britain ID Chart
Your personal guide to British Butterflies. This 8-panel laminated chart is designed for speedy butterfly identification in the field. Ideal for anyone interested in identifying butterflies, perfect for children and adults and ideal for outdoor use, laminated, shower-proof and robust. Get your copy today.
Butterflies of Britain (Laminated ID Chart).
Online store
Visit our online store for many more butterfly related books and gifts.
Population trends 1
UK Population trend 1995-2004 insuficient data
UK Population trend 1976-2004 insuficient data

1Fox, R., Asher. J., Brereton. T., Roy, D & Warren, M. (2006) The State of Butterflies in Britain & Ireland, Pices, Oxford.
UK BAP status 2
UK BAP status species of conservation concern (link)

2For information about the UK Biodiversity Action Plan, visit the JNCC web site jncc.defra.gov.uk.

National Biodiversity Network Gateway
National Biodiversity Network Gateway Distribution Map



Areas in and indicate a contraction in distribution of the Black Hairstreak except in Ireland where data is only available up until 1999.

* Records shown in outside the natural distribution may be the result of illegal or accidental releases by breeders or, depending upon the species, migrant individuals from mainland Europe.

Key to map*
= 2000 to 2010 inclusive (current distribution)
= records from 1950 to 1999 inclusive
= records from 1900 to 1949 inclusive
Records prior to 1st January 1900 are not shown.

The NBN Gateway records are shown on the map right. (See terms and conditions).

More data is available on the Black Hairstreak on the NBN Gateway web site.
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References
For full details of books and reports mentioned on this web site, view the references page.

Find out more online*
Black Hairstreak can be found on Peter Eeles excellent UK Butterflies web site.
Black Hairstreak can be found on Matt Rowlings excellent European Butterflies web site.

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Photographs of the Black Hairstreak
Image ID BB1736 - Black Hairstreak - © Debbie Cheshire
Black Hairstreak (imago)
BB1736 ©
Image ID BB1735 - Black Hairstreak - © Steven Cheshire
Black Hairstreak male (imago)
BB1735 ©
Image ID BB1734 - Black Hairstreak - © Steven Cheshire
Black Hairstreak male (imago)
BB1734 ©
Image ID BB1733 - Black Hairstreak - © Steven Cheshire
Black Hairstreak female (imago)
BB1733 ©
Image ID BB1732 - Black Hairstreak - © Steven Cheshire
Black Hairstreak female (imago)
BB1732 ©
Image ID BB1731 - Black Hairstreak - © Steven Cheshire
Black Hairstreak female (imago)
BB1731 ©
Image ID BB1730 - Black Hairstreak - © Steven Cheshire
Black Hairstreak female (imago)
BB1730 ©
Image ID BB1729 - Black Hairstreak - © Steven Cheshire
Black Hairstreak female (imago)
BB1729 ©
Image ID BB1728 - Black Hairstreak - © Steven Cheshire
Black Hairstreak male (imago)
BB1728 ©
Image ID BB551 - Black Hairstreak - © Steven Cheshire
Black Hairstreak female (imago)
BB551 ©
There are 27 photographs of the Black Hairstreak in our stock photo library.
View more photographs of the Black Hairstreak as a thumbnail gallery or as a slideshow.
Aberrations and forms
There are 3 named aberrant forms of the Black Hairstreak currently listed. Find out more about aberrants here.

ab. excessa - Tutt 1907
ab. lutea - Tutt 1907
ab. progressiva - Tutt 1907