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Brown Hairstreak in Worcestershire - Bulletin 13

August 2005

Dear Brown Hairstreakers,

The Brown Hairstreak year in Worcestershire can increasingly be divided into four distinct phases all of which bring their own particular challenges. Firstly, there is the period which usually in our case starts post Xmas and goes on to March, when we risk hypothermia and look for eggs. The second phase runs from roughly mid-April to the middle of June when, in generally milder conditions, we try to follow the caterpillars from first hatching through to when they are fully grown and ready to pupate. Probably the main risk here is getting jabbed in various parts of the anatomy by blackthorn spines and surrounding vegetation. Mid-July to late August, as we have newly discovered this year, is the time to look for Brown Hairstreaks on their assembly trees and almost certainly develop a stiff neck. Finally, and slightly overlapping, phase 4 is from now to the beginning of October when there are good chances to find female Brown Hairstreaks low down basking in the sunshine or egg laying on blackthorn plants. The main risk here is feeling foolish when people turn up from all points of the compass on an organised event in expectation of seeing a Brown Hairstreak and you fail to find one..... but more of this later.

Following our report in the last Bulletin, there have been several more sightings of Brown Hairstreaks both on assembly trees and at low level. Firstly, on 14th August, Bob Steele had another view of a male on angelica quite late in the afternoon further along the same ride where we had captured the individual in the beer glass the previous week (perhaps we should call this one the Brown Ale Hairstreak). Two days later, John Tilt managed a photo of another male (see below) within the south ride in Grafton perching on pendulous sedge and also bramble. His subsequent transect walk on the same day produced a female on the south side of the wood and, even better, two females egg-laying on the hedge to the west of the wood which we had only cut last year. Appreciative lot these Brown Hairstreaks.
 

I suspect that male Brown Hairstreaks are already on the wane. Rob and Rose Mabbett returned to the assembly tree at the south-west corner of the wood on 20th where they had previously seen up to 5 adults on their previous visit and, despite another marathon stint with the telescope, failed to locate any more. They did find, however, six freshly laid eggs on a single small blackthorn plant just a few metres from the tree so obviously it was mission accomplished as far as the males were concerned. The sighting of Silver-washed Fritillary and Brown Argus was also some compensation. I had a bit more success the following day when I returned to the ash tree mentioned in the last bulletin, below which a female had been seen on 7th, and saw two male Brown Hairstreaks involved in aerial combat. Eventually, managed to locate the two individuals in my scope, high in the canopy but some distance apart. They both looked fairly worn, with tears in their wings and missing tails. Moving a little further along the track, I then found two more, this time a male and female noticeably fresher, again quite high up on a tallish ash. Their behaviour was interesting as they were facing each other on a stem but after a few seconds would fly off only to return to the same part of the tree. They repeated this behaviour two or three times before I eventually lost them in the foliage. I can only presume this was part of a courtship ritual and would be interested to hear from anyone who has witnessed similar behaviour.

Anyway, back to phase 4 and potentially feeling foolish. Our Brown Hairstreak Local Champions Day this year is set for Sunday, 4th September meeting at the Three Parishes Hall at Grafton Flyford for 10.00 am. Our Regional Officer, Jane Ellis and myself will be giving a presentation on the Brown Hairstreak in Worcs followed by a walk in the hopes of finding at least one adult on the wing but no guarantees. John Tilt has already received a number of phone calls from people planning to attend so we hope to have a successful day. With the Brown Hairstreak, it is definitely a question of the more eyes the better, so please try to come and bring with you binoculars, telescopes and mobile phones! There will be refreshments on offer at the Village Hall courtesy of Miriam Tilt, so hopefully see you all then. In the meantime, if you have any Hairstreak news do get in touch.

Mike Williams,
Brown Hairstreak Species Champion