White-letter Hairstreak

The blog should really be about the Black Hairstreak. I made a third trip over to Ditchling Common to see them. As before they were visible but they were staying high in the trees. Others have had good picture opportunities this year but it just hasn't worked for me. Strange when I had such good views last year.

My best shot for this year below and just to prove I can take a decent picture, one from last year.

Black Hairstreak

Black Hairstreak  Ditchling Common 2018

I saw three large Fritillaries but none were stopping and I could not be sure on identification between Dark Green and Silver-washed. There were also a couple of views of Purple Hairstreaks but again staying distant at the tops of trees.

There were also a good few Painted Ladies around and a couple of Red Admirals. The later giving a closed wing view for long enough for me to get a picture. Interesting but as always with this butterfly the depth of red that we see with the eye just doesn't get recorded when photographed.

Red Admiral

Looking for a bit more success I moved on to Hollingbury Park to look for the White-letter Hairstreaks. There are always a good display of thistles here and once down and nectaring these butterflies are easier to photograph.

White-letter Hairstreak - male

White-letter Hairstreak - female

And a few Damselflies recorded at Woods Mills.

Azure Damselfly

Beautiful Demoiselle

Large Red Damselfly

Black Hairstreak

Black Hairstreak colony found in Sussex. It sounds ridiculous, an early April Fools joke perhaps, but it appears to be true.

The butterflies are certainly there, on Ditchling Common, but how did they get there? The size and spread of the population suggests that the colony must have been established a long time ago. The best suggestion at the moment is that they were introduced in the 60s or 70s and have sat there, unnoticed for the past fifty years, slowly expanding their territory.

Fifty years without being noticed, it sounds unlikely but then these butterflies have a very short flight period, they stay mostly in the tops of trees, and this is probably not a well watched site for butterflies. With reports of 90+ Black Hairstreaks counted on one day this could well be one of the most numerous sites in the country.

There were a lot of people there today trying to photograph the butterflies and the area is getting a bit trampled. I expect it will be even worse by the end of the weekend. It's a pity that we do so much damage in our pursuit of a good picture.

For me the best aspect of the visit was that the butterflies were coming down onto the bracken and  also nectaring on the brambles making them easier to see. On other sites I had only ever found them in the tops of trees or down nectaring at heights of around six to ten feet.

I understand further investigation of various records is being carried out in an attempt to identify the source of the introduction. However their presence in Ditchling Common raises a number of questions. This is a species that although considered scarce and very localised, does exist over a huge range through Europe, Asia, and as far as Japan. We assume that in the UK they can only exist in the belt of land through Oxfordshire, Northamptonshire and into Cambridgeshire but why should this be. Habitat requirements do not seem to be particularly onerous and could exist almost anywhere in the south of the country.

There have been many records for the Black Hairstreak from the South of England. A number of colonies were identified in the Surrey area in the 70s and the assumption was made that these had spread from an introduction near Cranleigh in 1952 *. Possible but this is a highly sedentary butterfly. These colonies were all viable and only appear to have been lost through habitat destruction.

There are also historical records for elsewhere in the south of England but these are now all considered to have been misidentifications of the White-letter Hairstreak.

Perhaps the ramblings of a half informed amateur, but could there be more colonies out there in the South of England waiting to be found.

I have no qualms about adding it as number 47 on my Sussex list. People will argue the merits of introducing a species into an area where it has not existed before but these have now survived for about fifty generations and they still look to be prospering. That's good enough for me.




*(PDF) Black Hairstreak. Available from: https://www.researchgate.net/publication/275958378_Black_Hairstreak [accessed Jun 14 2018].

Black Hairstreak

Yesterday we got to see the Black Hairstreak butterflies at Bernwood Forest near Oxford. They were a life tick and it seemed like a great day. That was until we got home and found that we had missed ten Bee Eaters in Sussex. There was nothing we could have done about it, which is just as well, as I am not sure which I would have chosen if I had to pick between the two.

We were lucky to find the Black Hairstreaks. The weather had been poor on the way up but started to brighten up as we got there. The forest is large and we would have had little chance of finding the colony if Dave had not been able to get information on it from a contact.

Even then, when you were standing in the right spot, they were hard to see. Much of their time is spent feeding on honey dew in the tops of large trees and they only occasionally come down to nectar, usually on the flowers of Wild Privet. We probably saw about six specimens with a maximum of three flying at any one time. Only one of them came down to eye level and gave good photographic opportunities and as you would expect that was a really tatty specimen. All my shots were taken with a 400mm Telephoto lens with the macro staying in the bag all day.

First record shot

You always feel a lot happier once you have that first record shot. You can then relax and start the endless process of trying to get a decent picture. The shot above was actually the second Black Hairstreak that we saw, the first having been disturbed by a bee just as I was about to press the shutter release.

Not only were the butterflies staying high, they were also being silhouetted against a very bright sky making it hard to get a decent picture.

The very bright Wild Privet flowers do not help.

But at least most of the specimens we saw looked to be in good condition.

The shots of the Black Hairstreaks came out better than I had been expecting although you are rarely  satisfied with what you get. It feels good to have this one in the bag though, as I was expecting it to be a lot harder to find.

For once there are no other pictures. This was really a search for one butterfly. No mission creep, that could distract us from our target, being allowed. A succesful day, it's just a pity about the Bee Eaters.