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Black Hairstreak (Satyrium pruni)

On this page, we have made available all the information we have for this species

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Picture of Black Hairstreak
© Nick Greatorex-Davies

In Britain the Black Hairstreak is a rare butterfly with a very restricted distribution. It is a sedentary and elusive butterfly of old Blackthorn (Prunus spinosa) scrub in woodland or on, or adjacent to, woodland edges. (For further details on this species see

Family : Lycaenidae

Status : Stable

Status details :
Status since 1995 is Stable with a increase of 23%
Status over the last 20 years is Stable with a increase of 65%
Status over the last 10 years is Stable with a increase of 5%

Log collated index plot

Species Log Collated Index Plot

This chart shows the index of abundance (LCI = Log Collated Index) over time. It shows fluctuations in populations from year to year, and is scaled so that the average index over the whole series is equal to 2 (horizontal line). For greater detail about how this index is derived, click on the green question mark above.

Trend description :
Although this normally canopy dwelling butterfly is recorded occasionally on transects, the transect method is not suitable for monitoring changes in its abundance. The species has been recorded on only 12 UKBMS transects to date and has only been recorded regularly on a annual basis at more than one site for the past ten years or so and reflects the restricted distribution of this species. The limited data shows that the Black Hairstreak has been increasing at monitored sites with superb counts in recent years such as 2010.

This map shows the distribution between 1995 and 2016. Data is derived from the Butterflies for the New Millenium dataset via the NBN Gateway

Phenology plot
Species Phenology Plot

Phenology plot

This chart shows the average number of butterflies seen on transects between Arpil and October across all sites (fitted values from a Generalised Additive Model). The blue line gives average counts over the full BMS series (1976 to date) and the red line gives the average for the last year.

Species abundance map


This map shows symbols for the mean abundance at transect sites, with the colour of the symbol reflecting the level of abundance. Means are over all years. Grey background squares are the occupied cells as shown by the Butterflies for the New Millenium over the previous ten year period.


In total, Black Hairstreak has been recorded from 65 transects in the Butterfly Monitoring Scheme. Of these, annual indices of abundance have been calculated from 10 sites, with an average index of 2 individuals per site.

For 6 of these sites, Black Hairstreak has been recorded well enough to calculate annual indices of abundance in more years, allowing trends to be calculated.

In 2018, 43 individuals were recorded from 8 sites, producing annual indices at 7 of these.

The UK Butterfly Monitoring Scheme is organized and funded by Butterfly Conservation (BC), the Centre for Ecology and Hydrology (CEH), the British Trust for Ornithology (BTO), and the Joint Nature Conservation Committee (JNCC). The UKBMS is indebted to all volunteers who contribute data to the scheme.