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Thursday, 4 September 2025

Brown Hairstreaks Move East.

 Ever since I started to get interested in wildlife over 55 years ago, the Brown Hairstreak has always been a rare insect in East Sussex, whereas in West Sussex, it has always been quite common, despite being elusive.

I have searched for many years in sites across East Sussex that I have heard of occasional sightings, or those that looked as though they should hold the insect. So many hours spent, and yet I haven't had a single sighting east of Ditchling Common.

Well, that was until July 24th this year when I was doing my annual 2nd brood Wall Brown count. I was partly along the top path leading away from High and Over car park, when I saw a butterfly fluttering around some Blackthorn and Hawthorn bushes. Immediately I thought it looked like a probable Brown Hairstreak, but I needed it to land before I could confirm it. Fortunately, I managed to keep it in sight until it landed near the top of the Hawthorn and on looking through the binoculars, it was clearly a Brown Hairstreak. After walking this path reasonably regularly for well over 30 years at last my first Brown Hairstreak on my patch. The butterfly soon took flight again, but this time dropping down lower before settling again, in a position that I could get a record shot. It was a male Brown Hairstreak. This was even better news, as males generally hold a territory near where they emerged as the butterfly, which meant that there was a good chance that a female had laid eggs near here last year. Only time would tell if this was true, as other sightings would hopefully materialise over the next few weeks.


The Male Brown Hairstreak.

As it turned out, it was an excellent day, as apart from the Hairstreak, I also had a great Wall Brown count of 111 on my 4 mile circuit, my 3rd highest count.

Then, on 6th August, I was in the same area just hoping for another sighting. I spotted a Bordered Straw moth settle on the path in front of me which I photographed. Then as I started walking again I saw a female Brown Hairstreak settled on a leaf just by me. As it started fluttering about it became obvious that it was egg laying. I followed the butterfly for some time, as it flew from Blackthorn bush to another, in its search for egg laying sites. This was the proof I was after that eggs were laid nearby last year. It then improved even more on August 23rd with another egg laying female along Cradle Valley.


The Bordered Straw.



My first Seaford Female Brown Hairstreak.

On top of these sightings, Lisa and I went to another site near Arlington, where I had searched many times over the years, but had never seen them. On this occasion we were amazed to find 4 female Brown Hairstreaks over quite a large area. Once again, all of these were egg laying, so hopefully Brown Hairstreaks will become a much more regular sight in my local area in years to come.

With leading a Sussex butterfly tour during August, I have also been looking at several West Sussex sites. These included Burgess Hill and Steyning. On my first recce at the Burgess Hill site, I had just picked up my repaired binoculars from Park Cameras. I walked from there to the site and almost immediately saw the first hairstreak. It was a female that was soon chased by a male. 2 further females were also seen very quickly.









Burgess Hill female Brown Hairstreak.

I then did a recce at Steyning a few days before the tour, but I only had a short while due to another commitment. Although I only saw a single Brown Hairstreak I did decide that this site would probably be the best one to take the group, and just 3 days later this is where we went. Leading a group to see Brown Hairstreak is always a worry, as often this butterfly remains elusive, but on the tour, relief was quickly forthcoming with a sighting straight away, followed shortly by another. We then had an extended sighting of an egg laying female as she flew from bush to bush. For the hour plus that we were at the site we had almost continuous views of the butterflies.



Steyning female Brown Hairstreak.


Lisa and I then went to Steyning to look for the Brown Hairstreaks. This is a special place for us as it's where we first met 4 years ago while we were both there looking for Brown Hairstreaks. It was probably near peak in the flight season when we went there this year. We were on our own when we arrived, and once again, we started seeing the butterflies almost straight away. Between us we saw around 10 in the couple of hours that we were there. I'm sure I have seen far more Brown Hairstreaks this year than I have seen in a year before. It has been a very good year for this species, in both numbers and new sites. With so many eggs laid hopefully next year will show further spread into East Sussex.



Brown Hairstreak egg.

2 comments:

  1. I saw my first purple hairstreak this year, albeit a rather sick one

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  2. It is amazing how butterflies are moving in these last few years. We have been finding species moving north and now inland in Scotland. I had my first Speckled Woods here in the Central Scottish Borders two years ago and this year they have been really common. Wall Browns moved up the coast about 15 years ago and the have slowly spread inland, arriving here last year. After checking for years I found Purple hairstreaks here this year and they have been found all over the Lothians in the last couple of years. And White-letter Hairstreaks now seem to be resident in Edinburgh, having made it over the border four or five years ago. The Brown Hairstreaks are beautiful butterflies. I can't imagine they will get here any time soon!

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