Steyning Downland Scheme

A place to enjoy, A place to protect, A place to be proud of

The Brown Hairstreak Butterfly

  • One of the most interesting species we are fortunate to have on the SDS site is the Brown Hairstreak butterfly (Thecla betulae), currently listed on the UK Biodiversity Action Plan as a priority species.
  • This butterfly relies on relatively new Blackthorn growth in a warm sheltered site for egg-laying, depositing the egg in the fork of a branch. The reason we have a particularly good population here is because parts of the area are sheltered & south-facing and, as the site has been neglected for many years, the Blackthorn in the hedgerows has spread new growth into the meadows. The eggs are tiny and, when examined closely, look like minature sea urchins!
  • This is a beautiful and elusive species which often keeps hidden in the undergrowth. It was first noticed on the Rifle Range by Neil Hulme of the Sussex Butterfly Conservation who spotted some eggs in the winter of 2008. In his own words:
    • “The Rifle Range site was discovered on January 1st 2008, when I found a large number of eggs on the blackthorn and bullace near the ponds. On New Year's Day it's traditional for some to watch Morris Dancing, some to go pike fishing..... but I always go searching for Brown Hairstreak eggs on 'new' sites! The previous year I had similarly discovered a colony at Cissbury Ring. Searching for eggs in winter is by far the most successful way to locate this species, as it is Britain's most elusive butterfly. On the majority of known sites the adults are seldom if ever seen. West Sussex is one of the main strongholds of this localised and scarce species. I first spotted adult Brown Hairstreaks on the Rifle Range in early August 2008. This has since proven to be one of the very best sites in the UK for spotting the butterfly, and large numbers of enthusiasts now travel considerable distances to visit. The Brown Hairstreak is also present on Steyning Round Hill and over a wide area of the adjacent countryside.”
  • In the winter of 2009, as part of the preperations for fencing the Rifle Range in order to establish a grazing regime, a certain amount of scrub cutting was required. Unfortunately, due to a misunderstanding with the operators, rather more Blackthorn was cut than was necessary. This resulted in lots of good Brown Hairstreak habitat being destroyed. However, a prime area has now been fenced off to allow the Blackthorn to regenerate, and it is expected that the habitat will soon become even better. Populations will be closely monitored, and management practices developed accordingly.

Update: August 2010

It appears from observations made this month that the population of Brown Hairstreaks is very good in spite of the above-mentioned blackthorn cutting. On one day, Neil Hulme reckoned he saw 12 different females & 8 males on the site, which exceeds numbers seen last year. This is extremely encouraging as, because of the amount of strong blackthorn & bullace regrowth providing perfect egg-laying habitat, there is a strong chance of even better numbers next year. Watch this space!